Term
| Lecture: Cells and Embryology |
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Definition
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Term
| The CNS is composed of ___+___ and is connected to the periphery by __ pairs of cranial nerves and __ pairs of spinal nerves |
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Definition
| The CNS is composed of Brain+Spinal Cord and is connected to the periphery by 12 pairs of cranial nerves and 31 pairs of spinal nerves |
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Term
| The CNS is almost entirely derived from which embryologic layer? |
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Definition
| The Ectoderm (except one type of glial cell) |
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Term
| Describe the steps in forming the Neural Tube |
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Definition
During 3rd week of development, ectoderm along midline begins to thicken, forming neural plate
Day 18 - Neural groove, neural folds begin to form
Day 20 - Neural folds approach each other
Day 21 - Neural folds fuse across midline, forms tube which then sinks below surface ectoderm
Anterior neuropore closes on day 24, posterior neuropore closes on day 26 |
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Term
| ___ cells are derived from the neural tube while it's being formed and come to lie on either side of the tube |
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Definition
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Term
| What are the neural crest derived neural elements? |
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Definition
-Pseudounipolar neurons in dorsal root ganglion, sensory ganglia of some cranial nerves (V, VII, VIII, IX, X)
-Sympathetic and parasympathetic postganglionic neurons |
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Term
| What are the neural crest derived non-neural elements? |
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Definition
-Pia and arachnoid
-Schwann cells (glial cells myelinating peripheral nerves)
-Ciliary and papillary muscles of eye
-Chromaffin cells of adrenal medulla |
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Term
| Name the 3 Layers formed during Neural Tube Histogenesis and what they are the precursor for |
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Definition
1) Ependymal Layer (Ventricles)
2) Mantle Zone (Grey Matter)
3) Marginal Zone (White Matter) |
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Term
| Describe the process by which the 3 layers of the neural tube are formed |
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Definition
- Initially the neural tube consists of a single layer of pseudostratified, columnar epithelium (these form the ependymal layer immediately adj to the central canal which later becomes the ventricles)
- Cell free layer called the marginal zone surrounds the ependymal layer (formed due to division of cells from ependymal layer)
- Following the final division of ependymal layer cells, these cells begin to migrate away from the cavity and form the intermediate layer (called the mantle zone) between the ependymal layer and the marginal layer |
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Term
| What is the Sulcus Limitans? |
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Definition
| Formed from the ependymal layer, the sulcus limitans is a shallow, longitudinal groove separating the developing gray matter (formed from neuroblasts in the intermediate mantle zone) into a basal and alar plates along the length of the neural tube. |
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Term
| The Basal and Alar Plates are precursors for what in the spinal cord? |
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Definition
Alar plate precursor of dorsal horn in adult cord; associated with sensory function
Basal plate precursor on ventral horn in adult cord; associated with somatic motor function |
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Term
| Movement of the mantle layer to form the basal and alar plates are promoted by what two proteins? |
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Definition
| Movement of the mantle layer in these two direction is promoted by a couple proteins: Sonic hedgehog (promotes migration into the Basal plate) and bone morphogenetic protein (encourages migration into the Alar plate) |
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Term
| What lies between the alar and basal plates |
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Definition
| The intermediate grey which contains interneurons connecting the sensory and motor regions and at some levels also contains elements of the ANS |
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Term
| During the 4th week the ____ stage of brain development is established at the rostral end and by the 5th week the ___ stage is established. |
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Definition
4th week= 3 vesicle stage (or Primary Vesicle Stage)
5th week= 5 vesicle stage |
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Term
| Name the 3 Primary Vesicles |
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Definition
Prosencephalon (forebrain)
Mesencephalon (midbrain)
Rhombencephalon (hindbrain) |
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Term
| What are the two flexures formed at the 3 vesicle stage of neural development? Which one persists into adulthood? |
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Definition
Cervical Flexure: between the rhombencephalon and spinal cord and does NOT persist into adult CNS
Cephalic Flexure: at the level of the mesencephalon and persists as the bend between the axes of brainstem and forebrain |
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Term
| How do the 3 Primary Vesicles further subdivide into the 5 Vesicle Stage |
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Definition
1) Telencephalon (from Prosencephalon)
2) Diencephalon (from Prosencephalon)
3) Mesencephalon (from Mesencephalon)
4) Metencephalon (from Rhombencephalon)
5) Myelencephalon (from Rhombencephalon) |
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Term
| What flexure develops at the 5 vesicle stage and at what level |
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Definition
| Pontine flexure at the metencephalon level |
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Term
| How do the 5 vesicles subsequently develop into regions of the brain? |
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Definition
1) Telencephalon expands, eventually becomes cerebral hemispheres and basal ganglia (Caudate + Putamen)
2) Diencephalon becomes thalamus and hypothalamus, sub and epithalamus and other structures
3) Mesencephalon becomes midbrain
4) Metencephalon becomes pons; cerebellum develops from rhombic lip of metencephalon
5) Myelincephalon becomes medulla oblongata |
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Term
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Definition
| A developmental anomaly characterized by defective closure of the bony encasement of the spinal cord; the spinal cord and meninges may or may not protrude through the defect |
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Term
| Name the different types of Spina Bifida |
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Definition
1) Spina Bifida Occulta
2) Spina Bifida Aperta which consists of:
- Meningocele
- Myelomingocele
- Myeloschisis |
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Term
| Define Spina Bifida Occulta |
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Definition
| Spina Bifida in which there is a defect in the bony spinal canal (failure of vertebrae arches to close) without protrusion of the cord or meninges |
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Term
| Differentiate Meningocele, Myelomingocele and Myeloschisis |
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Definition
Meningocele: protrusion of the meninges
Myelomeningocele: protrusion of spinal cord
Myeloschisis: most severe, the vertebrae don't fuse and the neural tube doesn't close, neural tissue exposed to surface |
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Term
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Definition
| A congenital gap in the skull that usually results in a protrusion of brain material; forms a cyst |
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Term
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Definition
| Results from failure of anterior neuropore to close; the brain roughly from Rhombencephalon forward fails fully to develop; Incompatible with survival |
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Term
| What is the general role of the cell body or soma of the neuron |
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Definition
| To support the metabolic and synthetic needs of the neuron |
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Term
| T or F: A neuron contains all the usual organelles found in a cell |
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Definition
| True examples: RER (Nissl Substance), Golgi apparatus, Mitochondria |
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Term
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Definition
The cytoplasm of a neuron cell body exclusive of the nucleus and any processes i.e. dendrites or axons
Note: therefore perikaryon and soma can NOT be used interchangeably |
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Term
| Any branches off a neuron axon are called what? |
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Definition
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Term
| T or F: Dendrites contain many of the same organelles as the neuron soma |
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Definition
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Term
| A neuronal axon extends from what to what? |
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Definition
| The Axon Hillock to the Axon Terminal |
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Term
| Define Saltatory Conduction |
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Definition
| Saltatory conduction is the propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials. This only occurs in axons insulated by myelin! |
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Term
| What are the 3 types of synapses formed by axon terminals? Which are the two most common? |
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Definition
1) Axo-dendritic synapses
2) Axo-somatic synapses
3) Axo-axo synapses
Axo-dendritic and axo-somatic are most common |
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Term
| Define the Components of a Synapse |
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Definition
a. Presynaptic region the axon terminal
b. Synaptic cleft a narrow separation between two elements of synapse
c. Postsynaptic region consists of membrane of cell receiving synaptic input |
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Term
| Describe Generally the process of Synaptic Transmission |
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Definition
- Action potential arrives at terminal
- Ca++ enters terminal
- Promotes fusion of synaptic vesicle with presynaptic membrane
- Transmitter released into synaptic cleft by exocytosis
- Transmitter combines with receptor site in postsynaptic membrane
- Change in conductance in postsynaptic membrane
- Vesicle membrane "recycled" from presynaptic membrane into axon terminal
Note: Action of transmitter dependent upon nature of receptor. Excitatory synapses produce depolarization, hence excitation, of postsynaptic membrane (Often associated with asymmetrical synapses) and Inhibitory synapses produce stabilization or hyperpolarization, hence inhibition, of postsynaptic membrane (Often associated with symmetrical synapses) |
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Term
| Grey matter is where information is ___ whereas white matter is where it is __ |
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Definition
Grey= processed
White= transmitted |
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Term
| Grey matter consists of what components? White Matter? |
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Definition
Grey Matter= cell bodies, their dendrites and the synapses formed on them
White Matter= axons, along with their myelin sheaths |
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Term
| Lecture: Gross Anatomy I and II |
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Definition
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Term
| Grey matter is configured in a variety of ways including....? |
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Definition
| Central grey of cord, nuclei and cortical material |
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Term
| White matter is designated by various terms including....? |
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Definition
| Tracts, fasiculi peduncles |
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Term
| T or F: White matter is not only involved in transmitting information but also in altering it |
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Definition
| False! Only transmitting NO altering |
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Term
| The Spinal Cord extends from ___ to ___ |
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Definition
| From the Foramen Magnum to the Interspace btw L1-L2 |
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Term
| The tapered lower end of the Spinal Cord is called ___ |
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Definition
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Term
| What continues from the tip of the Conus Medularis? |
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Definition
| The filum terminale is a projection of pia matter from the conus medullaris extends down to connect it to the dorsal surface of the sacrum. |
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Term
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Definition
| The cauda equina (Latin for "horse's tail") is a bundle of spinal nerves and spinal nerve roots, consisting of the second through fifth lumbar nerve pairs, the first through fifth sacral nerve pairs, and the coccygeal nerve, all of which originate in the conus medullaris of the spinal cord. |
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Term
| Where are the cervical enlargement and lumbo-sacral enlargement found? What do they correspond to? |
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Definition
Cervical Enlargement: C5 to T1
Lumbo-Sacral Enlargement: L2-S3
The cervical enlargement corresponds to where the brachial plexus arises and the lumbosacral enlargement to where the lumbosacral plexus arises |
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Term
| What sensory information is associated with spinal nerves? |
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Definition
Somatosensation (general sensation): pain, touch, temperature, proprioception
NO special senses are associated with spinal nerves, they are all reflected by cranial nerves |
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Term
| 4 Basic Functions of the Brainstem |
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Definition
1) Regulating HR
2) Regulating BP
3) Regulating Breathing Patterns
4) Regulating Arousal and Alertness |
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Term
| What is the function of the cerebellum |
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Definition
| A motor structure involved in coordination and integration of movements initiated elsewhere, in particular from the cerebral cortex; operates subconsciously |
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Term
| The cerebellum is not part of the brainstem despite being derived from what? |
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Definition
| The Metencephalon (same as pons and initially derived form Rhomencephalon); note however it's connected intimately through a series of tracts called peduncles |
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Term
| List the Gross Morphological Features of the Medulla |
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Definition
a. Pyramids - Motor tract located on ventral surface of medulla
b. Olive - Lateral bulge, overlies nuclear group
c. Fasciculus gracilis and cuneatus, nucleus gracilis and cuneatus - Tracts and their respective nuclei located on dorsal surface of stem
d. Inferior cerebellar peduncle
e. Cranial nerves IX to XII
-CN IX: Glossopharyngeal nerve
-CN X: Vagus nerve
-CN XI: Spinal accessory nerve
-CN XII: Hypoglossal nerve |
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Term
| List the Gross Morphological Features of the Pons |
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Definition
a. Basilar pons and middle cerebellar peduncle - Tracts covering ventral surface of pons and continuing into cerebellum
b. Facial colliculus - Small bump on floor of IVth ventricle
c. Vestibular region - Area on floor of IVth ventricle overlying vestibular nuclei
d. Cranial nerves V to VIII
-CN V: Trigeminal nerve
-CN VI: Abducens nerve
-CN VII: Facial nerve
-CN VIII: Vestibulo-cochlear nerve (Auditory nerve) |
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Term
| List the Gross Morphological Features of the Mesencephalon |
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Definition
a. Basis pedunculi - Tract system on ventral surface of mesencephalon
b. Corpora quadrigemina - Two pair of bumps occupying dorsal surface of mesencephalon
-Lower pair the inferior colliculus
-Upper pair the superior colliculus
c. Superior cerebellar peduncle
d. Cranial nerves III and IV
-CN III: Oculomotor nerve
-CN IV: Trochlear nerve |
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Term
| Describe the Basilar Pons |
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Definition
| The large bulbous portion of the pons seen on the ventral portion of the brainstem and ventral to the medial lemniscus in a cross section: contains longitudinally oriented fibers (corticospinal, corticopontine, corticoreticular, and others) and the transversely oriented pontocerebellar fibers. The Basilar Pons aggregates laterally to form the middle cerebellar peduncle which relays information into the cerebellum about motor derived activity from the cerebral cortex |
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Term
| The Basis Pedunculi consists of numerous white matter tracts including the ____ tract which appears as the pyramids in the medulla. |
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Definition
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Term
| Describe the general function of the superior and inferior colliculi |
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Definition
Superior Colliculi: a nucleus that receives visual information and processes it to send it to a variety of structures that control neck and eye movements
Inferior Colliculi: the principle midbrain nucleus of the auditory pathway, receives auditory information from the cochlea and passes it to the next higher region before then sent to the cortex |
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Term
| What are the two regions of grey matter found in the cerebellum? |
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Definition
1) The cerebellar cortex
2) The cerebellar nuclei (sometimes called the deep cerebellar nuclei but these are the only ones so the term is a bit redundant) |
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Term
| Describe briefly the 4 components of the Diencephalon |
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Definition
Thalamus: comprised of a large number of nuclear groups, all sensory modalities (except olfaction) go through the thalamus which processes it before sending it to the cerebral cortex, a variety of motor structures also project into the thalamus i.e. cerebellar projections, reciprocally connected to the cerebral cortex
Hypothalamus: Involved with autonomic regulation, control of visceral function and maintenance of homeostasis through both conventional neural connections and endocrine control. Also connected to the limbic system.
Subthalamus: motor nucleus associated with the basal ganglia
Epithalamus:involved with gonadal maturation and diurnal rhythm, consists largely of the pineal body |
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Term
| T or F: The hypothalamus also consists of a large number of nuclei |
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Definition
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Term
| T or F: The term cerebrum is analogous to the cerebral cortex |
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Definition
| False, The cerebrum is a large part of the brain containing the cerebral cortex (of the two cerebral hemispheres), as well as several subcortical structures, including the hippocampus, basal ganglia, and olfactory bulb. |
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Term
| Name the 5 lobes of the cerebrum and give their rough location |
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Definition
Frontal Lobe: in front of the central sulcus
Parietal Lobe: behind the central sulcus and above the lateral sulcus
Occipital Lobe: posterior
Temporal Lobe: below the lateral sulcus
Insula: deep within the lateral sulcus |
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Term
| The Corpus Callosum is composed of ____ fibers, whereas the Internal Capsule is composed of ____ fibers |
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Definition
Corpus Callosum= comissural fibers (because they run at the same level)
Internal Capsule= projection fibers (because they connect two different levels of the CNS) |
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Term
| Name each of the ventricles and what part of the CNS they are associated with |
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Definition
Lateral Ventricles: Cerebral Hemispheres (anterior horn=frontal, body=parietal, posterior horn=occipital, inferior horn= temporal)
3rd ventricle: Diencephalon
Cerebral Aqueduct: Mesencephalon
4th Ventricle: Medulla and Pons
Central Canal: Spinal Cord (note: usually obliterated in adults) |
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Term
| What connects the Lateral Ventricles to the Third Ventricle? |
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Definition
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Term
| The Ventricles and ___ space are filled with CSF |
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Definition
| Subarachnoid Space (between the arachnoid mater and the pia mater) |
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Term
| CSF is manufactured by what? |
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Definition
| The choroid plexus, a vascular tissue extending into the ventricular spaces. There are four choroid plexuses in the brain, one in each of the ventricles. |
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Term
| Name the openings form which the CSF leaves the ventricular system to enter the subarachnoid space |
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Definition
| The median aperture (the foramen of Magendie), and the two lateral apertures (the foramen of Luschka) |
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Term
| T or F: The dura is attached to the bone in both the cranium and the vertebral canal |
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Definition
| False, the dura is adherent to the skull but is separated from the vertebral canal by an epidural space |
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Term
| T or F: the pia is adherent both to the brain and the spinal cord |
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Definition
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Term
| Where are the blood vessels on the surface of the brain lie in relation to the meningeal layers? |
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Definition
| They lie on the pia matter and when they penetrate to the surface of the brain they take short tuffs of pia matter into the brain |
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Term
| All blood vessels entering the brain, as well as cranial nerves pass through what space? |
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Definition
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Term
| Despite only accounting for 1/__ of human body weight the brain at rest consumes __% of oxygen that the circulatory system provides |
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Definition
| Despite only accounting for 1/50 of human body weight the brain at rest consumes 25% of oxygen that the circulatory system provides |
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Term
| Why is the brain so intolerant to cessation of blood supply? |
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Definition
| It has 0 glycogen reserves and is 100% dependent on the blood supply for all its nutrients and oxygen |
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Term
| Total cessation of blood supply will results in ____ in 10 secs,___ in 20 secs, and ____ in 3-4 mins |
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Definition
unconsciousness in 10 sec
decreased electrical activity in 20 secs
cell death in 3-4 mins |
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Term
| The brain is supplied by what 2 pairs of arteries |
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Definition
1) Vertebral Arteries
2) Internal Carotids |
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Term
| Where do the 2 pairs of arteries (vertebral and internal carotid) branch from? |
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Definition
1) Vertebral Arteries branch from the Subclavian Arteries
2) The Right Internal Carotid branches from the Right Common Carotid which comes off the R Brachiocephalic, the Left Internal Carotid branches from the Left Common Carotid which branches directly off the Aorta |
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Term
| Where do the 2 pairs of arteries (vertebral and internal carotids) enter the skull? |
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Definition
1) Vertebral: enter deep to the transverse process of the level of the 6th cervical vertebrae (C6), proceed in the transverse foramen and enter the skull via the foramen magnum
2) Internal Carotids: enter via carotid canal |
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Term
| T or F: The Internal Carotid has no branches exterior to the skull |
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Definition
| True, so if asked where a blood vessel in the neck is derived from the answer cannot be internal carotid |
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Term
| The arterial blood supply of the brain can be divided into what two systems |
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Definition
1) The carotid system: branches chiefly supplied by the internal carotid artery
2) The vertebral-basilar system: two vertebral arteries join after passing through the foramen magnum to form the basilar artery |
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Term
| Name the Components of the Carotid System |
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Definition
- The Anterior Cerebral and Anterior Communicating Arteries
- The Middle Cerebral Artery
- The Anterior Choroidal Artery (arises from MCA)
- The Posterior Communicating Arteries |
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Term
| Name the Components of the Vertebral Basilar System |
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Definition
Branches from the Basilar Artery
- The Posterior Cerebral and Posterior Choroidal Arteries
- The Superior Cerebellar Arteries
- The Pontine and Labyrinthe Arteries
- The Anterior Inferior Cerebellar Arteries
Branches from the Vertebral Artery
- The Posterior Inferior Cerebellar Arteries (PICA)
- The Anterior and Posterior Spinal Arteries |
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Term
| Which Artery connects the Carotid and Vertebral Basilar System? |
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Definition
| The Posterior Communicating Arteries: connects the MCA (carotid) with the PCA (vertebral-basilar) |
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Term
| Describe the Course/ Region Supplied by the Anterior Cerebral Arteries |
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Definition
Two ant cerebrals curl up around the corpus collasum to supply the middle surface of the frontal and parietal lobes
Ant cerebral gives off two major branches the pericallosal branch (which arches around the corpus callosum)and the colossal marginal branch which comes to surface of the hemispheres; branches of ant cerebral extend up through longituninal fissure to supply sup surface of frontal and parietal lobes
The two are connected by the Ant Communicating Artery |
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Term
| Describe the Course/ Region Supplied by the Middle Cerebral Arteries |
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Definition
Middle cerebral artery proceedes laterally under the cover of the temporal lobe and then spreads out in fan-like fashion over the lateral surface of the hemispheres supplying the lateral surface of the frontal, parietal, ant portions of occipital and upper two gyri of the temporal lobe; has a widespread distribution
Domain of the distribution of the branches include primary motor and primary sensory cortex; involved in issuing motor commands involved in voluntary muscle control and where you have conscious appreciation of somato-sensation (pain, temp, proroprioception and touch) |
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Term
| A stroke involving the MCA would result in what? |
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Definition
- Stroke involved with middle cerebral artery, depending on extend of infarct; compromises ability to execute voluntary movements and appreciate consciously sensation on CONTRALATERAL side of the body
- If strictly MCA the lower limbs may be spared because this area is also perfused by the Anterior Cerebral Arteries |
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Term
| Describe the Course/ Region Supplied by the Anterior Choroidal Artery |
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Definition
- Branch off the MCA
- Penetrates into substance of the brain to supply the choroid plexuses in the lateral ventricles
- Also supplies parts of the temporal lobe (limbic system), portions of midbrain, internal capsule and thalamus |
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Term
| Describe the Course/ Region Supplied by the Posterior Cerebral Artery |
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Definition
- Posterior Cerebral Arteries are the final branch of the Basalar which actually splits into the posterior cerebrals
- Posterior cerebral artery supplies the inferior surface of the temporal lobe, the medial surface of the occipital lobe and (like the anterior cerebral) extends onto the posterior and superior surface of the hemispheres
- There’s a branch of the posterior cerebral called Calcarine artery that is distributed to the portion of the occipital lobe involved in receiving primary visual information; direct input from the thalamus that relays visual information from the retina |
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Term
| What would be the result of an infarct affecting the calcarine artery |
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Definition
| Blindness in the contralateral visual field |
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Term
| Describe the Course/ Region Supplied by the Superior Cerebellar Arteries |
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Definition
- Arise just caudal to the posterior cerebral off the basilar
- Arches around the brainstem and supplies superior surface of the cerebellum, caudal midbrain and rostral pons |
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Term
| What important structure is found between the Posterior Cerebral Arteries and the Superior Cerebellar Arteries? |
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Definition
| The occulomotor nerve (CN III) therefore thrombosis here can cause nerve impingement |
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Term
| Describe the Course/ Region Supplied by the Pontine Arteries |
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Definition
| Number of small vessels off the Basilar that supply the basilar pons |
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Term
| Describe the Course/ Region Supplied by the Labyrinthe Artery |
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Definition
| Arises from the Basilar, a small artery that isn't actually a brain vessel it supplies the inner ear |
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Term
| Describe the Course/ Region Supplied by the Posterior Choroidal Arteries |
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Definition
| Branch off the Posterior Cerebral Artery, supplies the choroid plexus of the 3rd ventricle and the rest of the choroid plexus |
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Term
| Describe the Course/ Region Supplied by the Anterior Inferior Cerebellar Arteries |
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Definition
| Branch off the Basilar Artery, it curls around the brainstem and supplies the inferior surface of the anterior portion of the cerebellum and the posterior pons |
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Term
| Describe the Course/ Region Supplied by the Posterior Inferior Cerebellar Arteries |
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Definition
| The PICA curls around the medulla and supplies the lateral portions of the cerebellum and the dorsolateral part of the medulla |
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Term
| Define Wallenbergs Syndrome |
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Definition
| It is the clinical manifestation resulting from occlusion of the posterior inferior cerebellar artery (PICA) or one of its branches or of the vertebral artery, in which the lateral part of the medulla oblongata infarcts, resulting in a typical pattern |
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Term
| Describe the Course/ Region Supplied by the Posterior Spinal Arteries |
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Definition
| Courses down the spinal cord passing through the foramen magnum and supplies the cervical cord |
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Term
| Name the arteries that supply the cord caudally to the Posterior Spinal Arteries |
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Definition
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Term
| Describe the Course/ Region Supplied by the Anterior Spinal Artery |
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Definition
| Extends down ventral surface of the spinal cord; singular artery (unlike the posterior spinal arteries which are paired) |
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Term
| Define the Circle of Willis |
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Definition
| Series of anastomotic channels around base of the brain that connects carotid system to vertebral-basalar system. Theoretically provides pathway for development of collateral circulation in event of occlusion of one portion of arterial supply of brain, however often times this doesn't occur do you can't assume a shunt |
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Term
| Which blood vessels make up the Circle of Willis |
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Definition
- Anterior communicating artery
- Anterior cerebral artery (Proximal portion)
- Posterior communicating artery
- Posterior cerebral artery (proximal part) |
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Term
| What vessel type arises from the Circle of Willis? |
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Definition
| Penetrating or Ganglion vessels, a number of small vessels which penetrate the under surface of the brain and are named in terms of groups |
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Term
| Name the 4 Groups of Ganglionic (Penetrating Arteries) |
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Definition
1) AnteroMedial Group
2) AnteroLateral Group
3) PosteroMedial Group
4) PosteroLateral Group |
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Term
| Describe the Course/ Region Supplied by the Anteromedial Group |
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Definition
- Arises chiefly from the anterior communicating and anterior cerebral arteries
- Penetrates brain via the anterior perforated substance
- Supplies portions of the hypothalamus |
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Term
| What is the other name for the Anterolateral Group |
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Definition
| Lenticulostriate (lenticulo= arises from name given to some basal ganglia; striate= they penetrate into the internal capsule) |
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Term
| Describe the Course/ Region Supplied by the Anterolateral Group |
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Definition
- Arise from the middle cerebral arteries
- Penetrate the brain via the anterior perforated substance
- Supply much of the corpus striatum and the anterior limb, genu and much of the posterior limb of the internal capsule |
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Term
| Infarcts to the Anterolateral Group produce a characteristic lesion called a ___ |
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Definition
Capsular lesion
Ex: if you disrupt fibers from the Right cerebral hemisphere to tract you get Left paralysis and sensory problems |
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Term
| Describe the Course/ Region Supplied by the Posteromedial Group |
|
Definition
- Arise mainly from the posterior communicating arteries and the posterior cerebral arteries
- Penetrate the brain via the posterior perforated substance
- Supply much of the thalamus and hypothalamus, the subthalamus and some medial portions of the midbrain |
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|
Term
| Describe the Course/ Region Supplied by the Posterolateral Group |
|
Definition
- Arise from the posterior cerebral artery
- Supplies the posterior portion of the thalamus and the tectum and some lateral portions of the midbrain |
|
|
Term
| An aneurysm on the Circle of Willis is called what? |
|
Definition
| A Berry Aneurysm (often silent and dangerous!) |
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|
Term
| Lecture: Spinal Cord I and II |
|
Definition
|
|
Term
| Describe growth of the cord simultaneously to the vertebral column |
|
Definition
- For first 3 months of development the cord extends the entire length of the vertebral canal
- At birth it ends at L3
- Adult position of L1/L2 is the result of differentiated growth between the cord and vertebral column |
|
|
Term
| Where are the cervical and Lumbo-sacral enlargements |
|
Definition
Cervical enlargement: From C-5 to T-1 spinal segments
Lumbo-sacral enlargement: From L-2 to S-3 spinal segments |
|
|
Term
| As you ascend the cord caudal to rostral the amount of white matter ____ because.... |
|
Definition
| Amount of white matter increases because you have more and more sensory information to convey upwards and the greatest number of descending motor fibers at the top |
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|
Term
| The Cauda Equina is composed of what spinal nerves? |
|
Definition
| Cauda equina: L2-L5, S1-S5 and coccygeal |
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|
Term
| What does a cord segment mean? |
|
Definition
| Cord segment defined by number of spinal nerve arising form it; ex: if nucleus found between T1 and L2 then found in portions of cord that give rise to those spinal nerves; it DOES NOT refer to adjacent vertebrae because around T9 the cord is not opposite that vertebrae but nerve exits under that vertebrae |
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Term
| If there was a lumbar disc protrusion at disc level L4-5 which spinal nerve would it affect? |
|
Definition
| Lumbar disc protrusion does not usually affect the nerve exiting above the disc, lateral protrusion at disc level L4-5 affects L5 spinal nerve not L4 spinal nerve, it will sometimes even affect S1-S4 spinal nerves |
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Term
| Describe the relationship between the three meningeal layers to the spinal cord |
|
Definition
- Pia adherent to surface of the spinal cord
- Subarachnoid Space between Arachnoid and Pia filled with CSF
- Arachnoid adherent to the Dura matter which extends to the tip of the conus medularis and invelops the cauda equina
- Subdural space between the dura and the bony vertebral column filled with fat and venous plexuses |
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Term
| How can CSF samples be used diagnostically |
|
Definition
| CSF is largely a saline solution, low protein and no RBCs so if you see RBCs then you know there’s a problem in the CNS (ex tumour or stroke). very few white cells and low conc of proteins, if these are raised in CSF can suggest there’s an infection somewhere in the CNS (ex: meningitis) |
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Term
| Describe the difference between an epidural and a lumbar puncture |
|
Definition
| Epidural is done for anaesthetic and needle goes through bony column into epidural space i.e. above the dura. The dura and arachnoid are tightly adherent. A lumbar puncture goes through the dura/arachnoid into the subarachnoid space which has CSF therefore lumbar puncture always done at L3/L4 because the cord covered by pia has ended, the dura sac extends to the tip of the conus medularis and envelops the cauda equina |
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Term
| Define the Dentate Ligaments |
|
Definition
| The pia mater of the spinal cord has a pair of denticulate ligaments (one on each side of the spinal cord) with 21 attachments per side which attach it to the arachnoid and dura mater and suspend the spinal cord within the dural sheath. Note the attachment sites are between the dorsal and ventral roots. |
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Term
| The Spinal Grey is divided into what 3 regions? |
|
Definition
1) Dorsal horn: Receives input from dorsal root, sensory in function
2) Intermediate gray: Interposed between dorsal and ventral horns
3) Ventral horn: Includes neurons contributing to ventral root, motor in function |
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Term
|
Definition
| A collection of neurons of similar morphology, receiving similar information, and serving similar functions. Nuclei form columns of cells extending for varying distances throughout the cord |
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|
Term
| Cord Nuclei can be classified into what three categories? |
|
Definition
| Sensory, visceromotor (autonomic), and somatomotor |
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|
Term
| Name the main nuclei that fall into each of the three categories |
|
Definition
Sensory Nuclei: Substantia Gelatinosa, Nucleus Proprius (Dorsal Proper Nucleus), Nucleus Dorsalis (Thoracic Nucleus, Clarke's Column)
Visceromotor: Intermediate cell Column (lateral horn), Sacral Autonomic Nucleus (S2-S4)
Somatomotor: Lateral and Medial Ventral Horn Motor Nuclei |
|
|
Term
| Describe the Substantia Gelatinosa (i.e. where it's found and what it does) |
|
Definition
- Collection of small neurons 'capping' the dorsal horn
- Found throughout length of the cord
- Incoming dorsal root fibers conveying pain and temperature synapse here either on neurons in the nucleus or dendrites of neurons in the nucleus proprius which extend into this region
- Neurons in the substantia gelatinosa are involved in processing incoming pain sensations but do not give rise to axons conveying sensory information to higher levels; the neurons give rise to short axons that don't leave the spinal grey and only extend up or down a few levels |
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|
Term
| Describe the Nucleus Proprius (i.e. where it's found and what it does) |
|
Definition
- Located ventral to Substantia Gelatinosa
- Extends throughout the length of the cord
- Larger neurons than Substantia Gelatinosa
- Involved in processing Pain/Temp Info
- Neurons comprising this nucleus give rise to axons which cross the cord in the ventral white commissure and ascend contralaterally in the spinothalamic tracts |
|
|
Term
| Describe the Nucleus Dorsalis (i.e. where it's found and what it does) |
|
Definition
- Found between cord segments T1 and L2
- Conveys proprioceptive information from the lower limb and trunk to the cerebellum
- Neurons in this nucleus give rise to axons which ascend the cord ipsilaterally in the dorsal spinocerebellar tract |
|
|
Term
| Describe the Intermediolateral Cell Column i.e. Lateral Horn (i.e. where it's found and what it does) |
|
Definition
- Located between T1 and L3 spinal segments
- Nucleus consists of sympathetic preganglionic motor neurons whose axons exit with the ventral root the enter the sympathetic chain of ganglia via the white ramus comminicantes |
|
|
Term
| Describe the Sacral Autonomic Nucleus (i.e. where it's found and what it does) |
|
Definition
- Located between S2 and S4 spinal segments
- Site of parasympathetic preganglionic spinal outflow from the transverse colon onwards (where the vagus nerve leaves off)
- Note: although its found in the same location as the lateral horn is further up the cord, you don't actually get a lateral horn formed here since its such a small collection of neurons |
|
|
Term
|
Definition
|
|
Term
| Describe the Ventral Horn Motor Neurons |
|
Definition
- Ventral horn itself runs the whole length of the cord
- Very large alpha motor neurons
- May be roughly divided into medial and lateral groups; medial exists throughout cord, and supplies axial musculature; lateral only found in the cervical and lumbo-sacral swellings as it supplies appendicular musculature |
|
|
Term
| The Ventral Horn Motor Neurons are organized in what two ways? |
|
Definition
- Body is represented medial to lateral in the ventral horn in relation to its distribution of outflow from axial to appendicular
- Also oriented such that flexor motor neurons are more dorsal and extensor motor neurons are more ventral |
|
|
Term
| T or F: Axons are all relatively short |
|
Definition
| False, some can be very long ex: ventral motor neurons going from your lumbar spine down to your leg |
|
|
Term
| What is the Rexed's Laminae classification of Spinal Cord Grey Matter |
|
Definition
Grey matter described by morphology of neurons, don't need to know details but they are provided here just in case:
Lamina I - Posteromarginal nucleus; located outside substania gelatinosa
Lamina II - Substantia gelatinosa
Lamina III to VI - “Sensory processing region,” includes interneurons, nucleus proprius, spinothalamic tract neurons
Lamina VII - Intermediate gray, extending into ventral horn; interneurons; thoracic nucleus and lateral horn (where present)
Lamina VIII - Interneurons in medial portion of ventral horn
Lamina IX - Ventral horn alpha motor neurons
Lamina X - Region surrounding central canal; small neurons, glial elements |
|
|
Term
| Each spinal nerve consists of what two things? |
|
Definition
| A dorsal sensory root and a ventral motor root |
|
|
Term
| Where are the neurons located that supply the axons travelling through the dorsal root of the spinal nerve? |
|
Definition
| Axons are from pseudounipolar neurons located in the Dorsal Root Ganglia. It's characteristic of sensory neurons in periphery to be pseudounipolar meaning they give rise to a single axon from their cell body but the axon splits |
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|
Term
| The Dorsal Root can be divided into what two types of fibers based on morphology and function |
|
Definition
Medial Bundle: large heavily myelinated and rapidly conduction Aα and Aβ fibers that convey information relating to proprioception and fine touch; these axons then ascend in the ipsilateral dorsal columns
Lateral Bundle: smaller, lightly or unmyelinated slow conducting Aδ and C fibers which convey information about pain, crude touch and pressure both somatic and visceral; these axons tend to synapse in one or two segments in the susbstantia gelatinosa or nucleus proprius after which the cross and continue on the contralateral side |
|
|
Term
| The Ventral Root contains what two types of fibers |
|
Definition
Axons of alpha (lower motor) neurons distributed to skeletal muscles for voluntary and reflex control of striated muscle
Axons of autonomic preganglionic neurons involved in control of visceral muscles and glands (sympathetics in T1-L3 and parasympathetics in S2-S4) |
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|
Term
| What are the various pathways the sympathetic preganglionics can take once they leave the spinal nerve? |
|
Definition
Once they leave the spinal nerve they enter the sympathetic chain ganglia through the white ramus communicantes and which point they can:
A) Synapse in paravertebral ganglion (i.e. in the sympathetic chain) and then go back to enter spinal nerve via the grey ramus communicantes (grey b/c less myelinated), and get distributed to skin, muscles etc to act on things like sweat glands, glandular tissue, smooth muscles in blood vessels etc
B) Continue up and down the chain and synapse in higher/lower paravertebral ganglia
C) Traverse straight through the paravertebral ganglia to distribute via splanchnic nerves to prevertebral ganglia ex: celiac, superior mesenteric etc. |
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|
Term
| What path do the parasympathetic preganglionic neurons take? |
|
Definition
| Exit via the ventral root and are distributed to postganglionic neurons embedded in walls of the viscera (i.e. do not go through the sympathetic chain!) |
|
|
Term
| What is the simplest form of reflex arc? What else is involved in a less simple reflex arc? |
|
Definition
Simplest reflex arc: sensory nerve gives off collaterals with direct synaptic contact on a ventral motor neuron which then fires ex: patellar reflex
In higher order reflex arcs you have interneurons in intermediate grey, as well as higher level influences, and can even get crossing of the cord to have coordination of reflexes from side to side |
|
|
Term
| Describe the 4 Functional Components of the Spinal Nerve |
|
Definition
1) General somatic afferent (GSA): Somatosensation - Pain, temperature, touch, pressure, proprioception
2) General visceral afferent (GVA): Visceral sensory input such as distention pressure and pain in the gut, baro and chemo receptors
3) General somatic efferent (GSE): Voluntary and reflex control of somatic muscles
4) General visceral efferent (GVE): Autonomic control of visceral muscles and glands
Note: general means not a special sense because no spinal nerves carry special senses |
|
|
Term
| The Spinal Cord White Matter is divided into what 3 components |
|
Definition
Dorsal Funiculi: on the dorsal side from the middle to posterior horn
Lateral Funiculi: lateral to the grey matter
Anterior Funiculi: from the ventral motor horn output to the anterior median fissure |
|
|
Term
| Each funiculus is composed of a number of what? |
|
Definition
|
|
Term
| Differentiate a Tract from a Pathway |
|
Definition
- A tract is a collection of axons which transmits information of a kind specific to that tract
- These tracts are components of pathways which are involved in transmitting information of a particular kind up or down the CNS
- Pathways may consist of a number of tracts and nuclei |
|
|
Term
| The Dorsal Columns-Medial Leminiscal Pathway conveys what type of information |
|
Definition
| Proprioception, Fine Touch and Vibration |
|
|
Term
| What are the two Dorsal Columns and what information do they convey |
|
Definition
| The Medial Column is the Fasiculus Gracilis which conveys sensory information from the lower body/limbs, the Lateral Column is the Fasiculus Cuneatus which conveys sensory information from the upper body/limbs |
|
|
Term
| Draw out the steps for the Dorsal Column-Medial Leminiscal System |
|
Definition
|
|
Term
| T or F: the dorsal columns terminate in the soamtosensory cortex |
|
Definition
| False, it terminates in the nuclei in the medulla, the pathway ends there but the given TRACT (element of pathway) does not |
|
|
Term
| How are the fibers in the dorsal columns organized? |
|
Definition
| Somatotopically, with the foot medial and the hand lateral. Note: this is preserved in the medial leminiscus even after crossing has occurred. |
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|
Term
| A Penetrating wound at T5 segment that interrupted the fibres of the R fasiculus gracilis would cause what sensory loss and where? |
|
Definition
| A: proprioception, fine touch and vibration on the Right Side (hasn’t crossed yet) and below the T5 spinal segment (remember lower limb because fasiculus gracilis but doesn’t matter at T5 because you only have lower limb input here anyway) |
|
|
Term
| A Stroke on the R somato-sensory cortex that affects the parietal lobe on post-central gyrus. In relation to proprioception and fine touch, where would this person experience a deficit |
|
Definition
| Left side (pathway crossed on route; anything above the lower medulla will cause contralateral deficits) |
|
|
Term
| What Type of Information do the Dorsal and Ventral Spinocerebellar Tracts carry? |
|
Definition
| Unconscious proprioception, especially from the lower limb to the cerebellum. Note these are sensory pathways even though they go to a motor structure! These pathways pursue different courses but end up in the same place |
|
|
Term
| Draw out the Steps for both the Dorsal and Ventral Spinocerebellar System |
|
Definition
|
|
Term
| The Anterolateral System can for out purposes be restricted to what? |
|
Definition
| The Lateral Spinothalamic Pathway |
|
|
Term
| The Lateral Spinothalamic Pathway carries what information? |
|
Definition
|
|
Term
| Draw out the Steps for the Lateral Spinothalamic Tract |
|
Definition
|
|
Term
| Note: in regards to steps drawn for LST, there can sometimes be interneurons through the Substantia Gelatinosa, the neurons do not always synapse directly on Dorsal Proper Nucleus |
|
Definition
|
|
Term
| How is the LST organized? |
|
Definition
| Also somatotopically but in reverse to that of the dorsal columns. In the Dorsal Columns the foot was medial but for LST the hand is medial. This is because the LST crosses at the level of the spinal cord and info from the upper limb is the last to join the tract and therefore once it's crossed it is now medial |
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|
Term
| Hemisection of Lower Cervical Level on RHS would result in what sensory loses? |
|
Definition
| No proprioception on the RHS and no pain/temp on the LHS |
|
|
Term
| Q: Stroke on the left side somatosensory cortex that affects the whole thing, where would you see sensory lossed? |
|
Definition
| A: Proprioception and Fine Touch would be opposite side; Pain and Temp would be Opposite |
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|
Term
| People who have pain uncontrolled by opiods can have an LST tractectomy to remove the tract, however eventually pain will return. Why is this? |
|
Definition
| We know the fibers are not able to regenerate therefore it suggests there must be alternative pain pathways |
|
|
Term
| What type of information does the Corticospinal Tract convey |
|
Definition
| Two tracts involved in transmitting information from cerebral cortex to lower motor neurons for voluntary control of skeletal muscles particularly fine learned movements |
|
|
Term
| Draw out the Steps for the Corticospinal Tract |
|
Definition
|
|
Term
| First Order Neurons for the Corticospinal Tract come from what places in the cortex? |
|
Definition
30% from primary motor in the frontal lobe
30% from premotor cortex in frontal lobe
40% from sensory cortex in parietal lobe
(these all descend through the internal capsule and join the tract) |
|
|
Term
| T or F: The cerebral cortex is also somatopically organized with respect to motor outflow |
|
Definition
| True, a very similar homonculus can be drawn for motor outflow, i.e. with head on lateral aspect followed by hands etc and hips hanging over the longitudinal fissure |
|
|
Term
| The smaller ventral conticospinal tract probably only extends as far down as ___ |
|
Definition
|
|
Term
| Differentiate between UMN and LMN lesions |
|
Definition
Upper Motor Neuron
- Weakness
- Voluntary Paralysis/ Spastic Paralysis
- Inc Tone
- Inc Reflexes
- Babinski Reflex
LMN Lesions
- Weakness
- Flaccid Paralysis
- Dec Tone
- Dec Reflexes
- Muscle Wasting (atrophy) |
|
|
Term
| Why does the Babinski reflex reappear in UMN lesions |
|
Definition
| Normally in babies, as Corticospinal tract gets myelinated it dissapears because descending input in corticospinal tract suppresses this reflex, in injury that affects UMNs, that reflex re-appears |
|
|
Term
| Dorsolateral Tract (Tract of Lissauer): location, general pathway trajectory i.e. does it cross or not, and information type |
|
Definition
- Located btw peripheral margin of cord and tip of dorsal horn
- PAIN AND TEMPERATURE
- Short intersegmental tract
- Axons of lateral division of dorsal root enter cord, may extend a few segments up or down in this tract before entering grey matter |
|
|
Term
| Dorsal Columns: location, general pathway trajectory i.e. does it cross or not, and information type |
|
Definition
- FINE TOUCH, PROPRIOCEPTION, VIBRATION
- Bulk of Dorsal Funiculus
- Axons don't CROSS UNTIL caudal medulla |
|
|
Term
| Dorsal Spinocerebellar Tracts: location, general pathway trajectory i.e. does it cross or not, and information type |
|
Definition
- PROPRIOCEPTION from lower limb to cerebellum
- Enters cerebellum via the Inferior Cerebellar Peduncle
- Located at periphery of lateral funiculus
- UNCROSSED: cell bodies in ipsilateral nucleus dorsalis |
|
|
Term
| Ventral Spinocerebellar Tracts: location, general pathway trajectory i.e. does it cross or not, and information type |
|
Definition
- PROPRIOCEPTION from lower limb to cerebellum
- Enters cerebellum via the Superior Cerebellar Peduncle
- Also located at periphery of lateral funiculus
- CROSSES: cells of origin located contra-laterally at the base of the dorsal horn in the spinal grey |
|
|
Term
| Lateral Spinothalamic Tracts: location, general pathway trajectory i.e. does it cross or not, and information type |
|
Definition
- PAIN AND TEMPERATURE
- CROSSES: cells of origin located chiefly in contralateral nucleus proprius
- Input to neurons whose axons form this tract are derived from DRG cells that are located within a segment or two of the spinothalamic nucleus which they contact |
|
|
Term
| Ventral Spinothalamic Tracts: location, general pathway trajectory i.e. does it cross or not, and information type |
|
Definition
- LIGHT TOUCH
- CROSSES: cells of origin in contralateral nucleus proprius
- Neurons whose axons from ventral tract may receive input from DRG cells many segments removed from the location of the ventral spinothalamic neuron itself |
|
|
Term
|
Definition
|
|
Term
| List the Bones that make up the Cranium |
|
Definition
| (8): Frontal, 2 Parietal, 2 Temporal, Occipital, Ethmoid and Sphenoid |
|
|
Term
| List the Bones that make up the Facial Bones |
|
Definition
| (14): 2 inferior Nasal Conchae; 2 Lacrimal Bones; 2 Maxillae; 2 Nasal Bones; 2 Palatine Bones; 2 Zygomatic Bones; the Mandible and the Vomer. |
|
|
Term
| Which bones contribute to the bony orbit |
|
Definition
| Frontal, Sphenoid, Zygomatic, Maxilla, Ethmoid, Lacrimal |
|
|
Term
| Describe the various parts of the Temporal Bone |
|
Definition
1. Petrous part
a. Mastoid process
b. Styloid process
c. Tympanic cavity – middle ear; contains auditory ossicles
2. Tympanic part – tympanic ring, surrounds external acoustic meatus
3. Squamous part – flat part
a. Zygomatic process – part of zygomatic arch
b. Mandibular fossa with articular surface of temporomandibular joint |
|
|
Term
| Which bones make up the Anterior Cranial Fossa |
|
Definition
| Frontal, Ethmoid (cribiform plate) and Sphenoid (body and lesser wings) |
|
|
Term
| Which bones make up the Middle Cranial Fossa |
|
Definition
| Sphenoid (greater wing), Temporal, and Parietal |
|
|
Term
| Which important foramina are located in the Middle Cranial Fossa |
|
Definition
| Optic Canal, Superior Orbital Fissure, Foramen Spinosum, Foramen Ovale, Foramen Rotundum, Carotid Canal |
|
|
Term
| What travels through the optic canal? |
|
Definition
| Optic Nerve (CN II) and Opthalamic Artery |
|
|
Term
| What travels through the Superior Orbital Fissure? |
|
Definition
Oculomotor, Trochlear and Abducent Nerves (CN III, IV, VI)
Opthalamic Nerve (CN V1) |
|
|
Term
| What travels through the Foramen Rotundum? |
|
Definition
|
|
Term
| What travels through the Foramen Ovale |
|
Definition
|
|
Term
| What travels through Foramen Spinosum |
|
Definition
| Middle meningeal artery, a branch of maxillary artery |
|
|
Term
| What travels through the Carotid Canal |
|
Definition
| Internal carotid artery and sympathetic nerves |
|
|
Term
| Which bones make up the Posterior Cranial Fossa |
|
Definition
| Temporal (petrous part), Occipital, Parietal Bone |
|
|
Term
| Which important foramina are located in the Posterior Cranial Fossa |
|
Definition
| Foramen Magnum, Hypoglossal Canal, Jugular Foramen, Internal Acoustic Meatus |
|
|
Term
| What travels through the Foramen Magnum |
|
Definition
| Spinal Cord, vertebral arteries and spinal roots of accessory nerve (CN XI) |
|
|
Term
| What travels through Hypoglossal Canal |
|
Definition
| Hypoglossal nerve (CN XII) |
|
|
Term
| What travels through the Jugular Foramen |
|
Definition
Glossopharyngeal, Vagus and Accessory Nerves (CN IX, X, XI)
Internal Jugular Vein |
|
|
Term
| What travels through the Internal Acoustic Meatus? |
|
Definition
Facial Nerve (CN VII) which subsequently exits via the stylomastoid foramen
Vestibulocochlear Nerve (CN VIII) |
|
|
Term
| The Atlanto- Occipital Joint contributes to what type of movement for the head? What about the Altanto-axial joint? Cervical Spine Joints? |
|
Definition
Altalnto Occipital: FLEXION, EXTENSION i.e. nodding yes and some LATERAL FLEXION
Altanto Axial: ROTATION i.e. nodding no
Cervical spine joints: FLEXION AND LATERAL FLEXION |
|
|
Term
| Describe the Atlanto-Axial Joint |
|
Definition
| Formed between the odontoid process (or dens) of the axis and the ring formed by the transverse ligament of the atlas |
|
|
Term
| Name the Anterior Muscles that Move the Head |
|
Definition
Sternocleidomastoid
Anterior Vertebral muscles: rectus capitis anterior and lateralis, longus capitis, and longus colli
Lateral vertebral muscles: scalenus muscles |
|
|
Term
| What is the innervation for each of the Anterior Muscles that Move the Head |
|
Definition
Sternocleidomastoid= Spinal Accessory Nerve (CN XI)
Anterior Vertebral muscles (rectus capitis anterior and lateralis, longus capitis, and longus colli) and Lateral vertebral muscles (scalenus muscles)= ALL inervated by ventral rami of cervical spinal nerves NOT cranial nerves |
|
|
Term
| Sternocleidomastoid: Attachment and Action |
|
Definition
Superior attachment: mastoid process of temporal bone
Inferior attachments: sternal head of SCM- manubrium
clavicular head of SCM - sternal end of clavicle
Action: Unilateral contraction turns head to opposite side
Bilateral contraction extends superior neck and flexes inferior neck |
|
|
Term
| Anterior Vertebral Muscles: attachments for each and their collective action |
|
Definition
Rectus capitis anterior and lateralis: go from C1 to occipital bone
Longus capitis: from various cervical vertebrae to the occipital bone
Longus colli: from one cervical vertebrae to another
Action: flexion of neck at atlanto-occipital joint |
|
|
Term
| Scalenus muscles (lateral vertebral muscles): attachment and action |
|
Definition
Attachment: from rib #1 to cervical vertebrae
Action: Lateral Flexion of the Neck |
|
|
Term
| What is the general rule for how Superficial and Deep muscles of the back differ |
|
Definition
Superficial Muscles of the back involved mostly with moving the upper limb ( and are innervated by anterior rami of spinal nerves or CN XI)
Deeper, intrinsic muscles of the back, act on vertebral column and head ( and are innervated by posterior rami of spinal nerves) |
|
|
Term
| Name three Posterior Vertebral Muscles including their attachment and collective Action |
|
Definition
Splenius Capitis: from cervical vertebrae to mastoid process
Splenius Cervicus: from thoracic vertebrae to cervical vertebrae
Semispinalis Capitis: from cervical vertebrae to the occipital bone
Action: extend or rotate the head (to the same side) |
|
|
Term
| What muscles comprise the Suboccipital Muscles and what are their collective attachment Points and Action |
|
Definition
Suboccipital: (rectus capitis posterior minor & major, obliquus capitis superior & inferior)
Attachment: upper cervical vertebrae to occipital bone
Action: extend and rotate the head |
|
|
Term
| What makes up the TMJ and what actions can occur here |
|
Definition
The condylar process of the mandible articulates with the mandibular fossa of the temporal bone
Actions: mandible can be elevated (closed) or depressed (open the mouth) and protruded and retracted |
|
|
Term
| Name the 4 Muscles of Mastication |
|
Definition
| Masseter, Temporalis, Lateral Pterygoid and Medial Pterygoid |
|
|
Term
| Masseter: attachment and action |
|
Definition
Attachment: from maxilla and zygomatic bone onto the mandible (ramus)
Action: Elevation |
|
|
Term
| Temporalis: attachment and action |
|
Definition
Attachment: from temporal bone onto coronoid process of the mandible
Action: Elevation, Retraction |
|
|
Term
| Lateral Pterygoid: attachment and action |
|
Definition
Attachment: within the infratemporal fossa, from the lateral surface of the lateral pterygoid plate of the sphenoid to the neck and articular disk of the mandible at the TMJ
Action: Protrusion (pulls the condyles out of the mandibular fossa) and side to side movement of the mandible |
|
|
Term
| Medial Pterygoid: attachment and action |
|
Definition
Attachment: from the medial surface of the lateral pterygoid plate of the sphenid to the medial surface of the mandible (ramus)
Action: Elevation of mandible and side to side movement |
|
|
Term
| All the muscles of mastication are innervated by what nerve specifically? |
|
Definition
| The mandibular branch of the trigeminal nerve (V3) which exits the skull via the forament ovale and emerges within the infratemporal fossa |
|
|
Term
| What additionally assists in depression of the mandible? |
|
Definition
| Gracity! and additional muscles (digastric, geniohyoid, myohyoid i.e. suprahyoid muscles) |
|
|
Term
| Are the suprahyoid bones considered muscles of mastication? |
|
Definition
|
|
Term
| What innervates the Suprahyoid muscles |
|
Definition
| Anterior rami of spinal nerves C1-C3 |
|
|
Term
| All muscles of facial expression are innervated by what nerve (also include its branches!) |
|
Definition
| All the muscles of facial expression are innervated by the facial nerve (7th cranial nerve) that exits the skull via the stylomastoid foramen of the temporal bone where it then divides into five major branches: temporal, zygomatic, buccal, mandibular, cervical. |
|
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Term
| Define the borders of the Anterior Triangle of the Neck |
|
Definition
| Anterior triangle is bordered by the anterior midline of the neck, the anterior edge of the sternocleidomastoid muscle, the inferior border of mandible. |
|
|
Term
| Define the borders of the Posterior Triangle of the Neck |
|
Definition
| Posterior triangle is bordered by the posterior edge of the sternocleidomastoid muscle, the clavicle, the anterior edge of trapezius and occipital bone. |
|
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Term
| Important vessels & nerves within the anterior triangle of the neck: |
|
Definition
1. Internal and external carotid arteries at or above the bifurcation of the common carotid artery.
2. Internal jugular vein.
3. Portions of cranial nerve VII (facial).
4. Portions of cranial nerve IX (glossopharyngeal).
5. Portions of cranial nerve X (vagus).
6. Proximal portion of CN XI (spinal accessory nerve).
7. Cranial nerve XII (hypoglossal). |
|
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Term
| The portion of the anterior triangle containing the external and internal carotid arteries is called what? |
|
Definition
| The carotid triangle (borders formed by certain supra- and infra- hyoid muscles) |
|
|
Term
| How does the origin of the common carotid differ from L to R? |
|
Definition
| Recall that the common carotid originates from the arch of the aorta on the left and from the brachiocephalic trunk on the right. |
|
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Term
| Describe the course of the internal jugular vein through the anterior triangle |
|
Definition
| internal jugular vein drains blood from the brain exiting the skull via the jugular foramen (occipital bone) and passes through the anterior triangle of the neck to reach the subclavian vein. |
|
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Term
| Describe the course of the Facial Nerve through the anterior triangle |
|
Definition
| After exiting the skull through the stylomastoid foramen, portions of cranial nerve VII (facial nerve) pass through the superior aspect of the anterior triangle of the neck. |
|
|
Term
| Describe the course of CN IX, X and XI through the anterior triangle |
|
Definition
3 cranial nerves exit through the jugular foramen and pass through the anterior triangle:
1. The glossopharyngeal nerve (cranial nerve IX), especially the branches to the pharynx, pass through the superior aspect of the anterior triangle of the neck.
2. Branches of the vagus nerve (CN X), to the pharynx, also pass through the superior aspect of the anterior triangle of the neck. Most of the nerve descends within the carotid sheath with the common carotid artery and internal jugular vein.
3. After exiting the jugular foramen, the proximal portion of the spinal accessory nerve (CN XI) passes through the superior aspect of the anterior triangle of the neck, on its way to innervate sternocleidomastoid and trapezius. |
|
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Term
| Describe the course of CN XII through the anterior triangle |
|
Definition
| After exiting the hypoglossal canal, the hypoglossal nerve (CN XII) also passes through the superior aspect of the anterior triangle of the neck, on it way to innervate the intrinsic muscles of the tongue. |
|
|
Term
| List the important vessels & nerves found within the posterior triangle of the neck: |
|
Definition
1. External jugular vein.
2. Continuation of CN XI (spinal accessory nerve).
3. Phrenic nerve.
4. Proximal portion of the brachial plexus. |
|
|
Term
| Describe the course of the external jugular vein through the posterior triangle |
|
Definition
| The external jugular vein drains face, scalp, etc. Superficial to sternocleidomastoid over most of its course; it enters the inferior portion of the posterior triangle of the neck where is drains into the subclavian vein. |
|
|
Term
| Describe the course of the spinal accesory nerve (CN XI) through the posterior triangle |
|
Definition
| The spinal accessory nerve (CN XI) continues through the posterior triangle of the neck; innervated trapezius. |
|
|
Term
| Describe the course of the phrenic nerve through the posterior triangle |
|
Definition
| Another important nerve found in the inferior part of the posterior triangle of the neck is the phrenic nerve. It is derived from C3-C5 spinal nerves and passes into the thorax where it innervates the diaphragm. |
|
|
Term
| Describe the course of the brachial plexus through the posterior triangle |
|
Definition
| In the inferior portion of the posterior triangle emerge initial parts of the brachial plexus (between the anterior and middle scalene muscles, the interscalene triangle), the nerve supply to much of the upper limb, derived from spinal nerves C5-T1. |
|
|
Term
|
Definition
|
|
Term
| What additional types of fibers are found in Cranial Nerves that aren't seen in Spinal Nerves |
|
Definition
Cranial nerves have three additional (“special”) functional
components: special visceral efferent (SVE), special visceral afferent (SVA) and special somatic afferent fibers (SSA), in addition to the four (“general”) fiber types also found in spinal nerves (i.e., GSE, GVE, GSA, and GVA).
SVE fibers innervate skeletal muscles derived from the
embryonic pharyngeal arches. Special sensory fibers arise from special sense organs: SSA from eye and ear, and SVA from olfactory epithelium and taste buds. The GVE fibers of cranial nerves may be parasympathetic (from brainstem and cranial ganglia) or sympathetic (from cervical sympathetic trunk). |
|
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Term
| What are other names used to describe the Special Visceral Efferents |
|
Definition
| Branchial Motor or sometimes simply referred to as Somatic Motor. |
|
|
Term
| Which of the Cranial Nerves are Pure Sensory? |
|
Definition
| Olfactory (CN I), Optic (CN II) and Vestibulocochlear (CN VIII) |
|
|
Term
| Which of the Cranial Nerves are Pure Motor |
|
Definition
| Occulomotor (CN III), Trochlear (CN IV), Abducens (CN VI), Accessory (CN XI) and Hypoglossal (XII) |
|
|
Term
| Which of the Cranial Nerves are Mixed? |
|
Definition
| Trigeminal (CN V), Facial (CN VII), Glossopharyngeal (CN IX), Vagus (X) |
|
|
Term
| Which of the Cranial Nerves contain SVE or Branchial Motor Fibers |
|
Definition
| Trigeminal (CN V), Facial (CN VII), Glossopharyngeal (CN IX), Vagus (X) and Spinal Accessory (XI) |
|
|
Term
Olfactory (CN I):
List the types of fibers contained in the cranial nerves and their subsequent functions |
|
Definition
| Special Sensory (SVA): Smell |
|
|
Term
Optic (CN (II)
List the types of fibers contained in the cranial nerves and their subsequent functions |
|
Definition
| Special Sensory (SSA): Vision |
|
|
Term
Oculomotor (CN III)
List the types of fibers contained in the cranial nerves and their subsequent functions |
|
Definition
Somatic Motor (GSE): Innervates Superior, Medial and Inferior Rectus, Inferior Oblique and Levator palpebrae
Visceral Motor (GVE): Parasympathetic to ciliary and pupillary constrictor muscles |
|
|
Term
Trochlear (CN IV)
List the types of fibers contained in the cranial nerves and their subsequent functions |
|
Definition
| Somatic Motor (GSE): Superior oblique muscle |
|
|
Term
Trigeminal (CN V)
List the types of fibers contained in the cranial nerves and their subsequent functions |
|
Definition
Brachial Motor (SVE): Muscles of mastication
General Sensory (GSA): Sensory for the Anterior Head/Neck i.e. Face Mask Area |
|
|
Term
Abducens (CN VI)
List the types of fibers contained in the cranial nerves and their subsequent functions |
|
Definition
| Somatic Motor (GSE): Lateral Rectus |
|
|
Term
Facial (CN VII)
List the types of fibers contained in the cranial nerves and their subsequent functions |
|
Definition
Brachial Motor (SVE): Muscles of Facial Expression, Stapedius
Visceral Motor (GVE): parasympathetic to lacrimal gland via the pterygopalantine ganglia, and submandibular/sunlingual glands through the Submandibular ganglia
General Sensory (GSA): external ear
Special Sensory (SVA): taste for anterior 2/3 of tongue |
|
|
Term
Vestibulocochlear (CN VIII)
List the types of fibers contained in the cranial nerves and their subsequent functions |
|
Definition
| Special Sensory (SSA): hearing and balance |
|
|
Term
Glossopharyngeal (CN IX)
List the types of fibers contained in the cranial nerves and their subsequent functions |
|
Definition
Brachial Motor (SVE): stylopharyngeus- swallowing)
Visceral Motor (GVE): to parotid gland via the otic ganglion
Special Sensory (SVA): taste for posterior 1/3 of tongue, pharynx, carotid body and sinus
Somatic Sensory (GSA/GVA): external ear, general sensation for posterior one-third of the tongue |
|
|
Term
Vagus (CN X)
List the types of fibers contained in the cranial nerves and their subsequent functions |
|
Definition
Branchial Motor (SVE): pharynx-swallowing, larynx, levator veli palantini
Visceral Motor (GVE): parasympathetics thorax and abdominal viscera as far as the transverse colon
Visceral Sensory (SVA, GVA): epiglottis-taste, pharynx, larynx, trachea, esophagus and thoracic and abdominal viscera
Somatic Sensory (GSA): external ear |
|
|
Term
Spinal Accessory (CN XI)
List the types of fibers contained in the cranial nerves and their subsequent functions |
|
Definition
| Branchial Motor (GSE): to SCM and Trapezius |
|
|
Term
Hypoglossal (CN XII)
List the types of fibers contained in the cranial nerves and their subsequent functions |
|
Definition
| Somatic Motor (GSE): Intrinsic and Extrinsic Muscles of the Tongue except Palatoglossus (CN X) |
|
|
Term
| What are important general rules for neuronal location for CNs |
|
Definition
- The lower motor neurons of CNs are located within the CNS
- Most sensory neurons are located within ganglia – there are a few special cases
- The pre-ganglionic component of all autonomics associated with CNs (all parasympathetic) arise within the CNS, but the post-ganglionic neurons are contained within ganglia. |
|
|
Term
| Describe the course travelled by the Olfactory Nerve (CN I) |
|
Definition
| The olfactory nerves arise from specialized olfactory receptor neurons in the nasal mucosa through the cribriform plate (ethmoid bone) and terminate in the olfactory bulb. The olfactory tract then connects it to the brain. Note; the olfactory bulb and olfactory tract are not synonymous with olfactory nerve |
|
|
Term
| Describe the course travelled by the Optic Nerve (CN II) |
|
Definition
| The optic nerve contains the axons of retinal ganglion cells and enters the skull through the optic canal (sphenoid). |
|
|
Term
| The Superior Orbital Fissure is cleft formed between what two things? |
|
Definition
| The superior orbital fissure is a cleft between the lesser and greater wings of the sphenoid bone. |
|
|
Term
| Again, which nerves exit via the Superior Orbital Fissure> |
|
Definition
| CN III, IV, VI and V1 of the trigeminal |
|
|
Term
| Describe the course of parasympathetic fibers in CN III |
|
Definition
| The oculomotor nerve also carries pre- ganglionic parasympathetics to the ciliary ganglion within the orbit. Post-ganglionic parasympathetics then project to the eye via the short ciliary nerve. This parasympathetic pathway produces constriction of the pupil (miosis) and therefore can be tested by illuminating the eye. |
|
|
Term
| Describe the course of the motor fibers of CN V |
|
Definition
| Innervation of the muscles of mastication. This innervation is carried by the mandibular branch (V3) of the trigeminal nerve that exits the skull through the foramen ovale (sphenoid) passing through the infratemporal fossa. |
|
|
Term
| Describe the course for each of the sensory divisions of CN V |
|
Definition
Ophthalmic division (V1) enters the orbit through the superior orbital fissure, and some portions exit via the supra-orbital foramen
Maxillary division (V2) exits the skull via the foramen rotundum (sphenoid), and some branches enter the infra-orbital foramen
Mandibular division (V3) exits the skull via the foramen ovale and some exit via the Mental Foramen. |
|
|
Term
| The Corneal Reflex involves what Cranial Nerves |
|
Definition
| Sensory limb of reflex mediated by CN V and the motor limb mediated by CN VIII |
|
|
Term
| Describe the course for the Facial nerve (CN VII) including the names of its branches |
|
Definition
| Exits the skull by first passing into the internal acoustic meatus and through the facial canal (temporal bone), and then out the stylomastoid foramen (temporal bone) where it then divides into five major branches: temporal, zygomatic, buccal, mandibular, & cervical. |
|
|
Term
| Describe the course for Taste Fibers associated with the Facial Nerve |
|
Definition
This is actually (and confusingly!) carried initially by the lingual nerve, a branch of the mandibular nerve (V3). The fibres are then by the chorda tympani that joins the facial nerve within the facial canal.
Note: the chorda tympani enters through the petrotympanic fissure and then passes through the middle ear to reach the facial canal. We ascribe taste to the facial nerve because it's the nerve that eventually sends the information to the brain |
|
|
Term
| Describe the course for the Parasympathetic fibers in the Facial Nerve that supply the Lacrimal Gland |
|
Definition
| Within the skull, the facial nerve gives rise to a branch, the greater petrosal nerve. In this branch are pre-ganglionic parasympathetics that exit the skull at the pterygoid canal to reach the pterygopalatine ganglion within the pterygopalatine fossa. Post-ganglionic parasympathetics then project via a branch of the maxillary nerve (V2) to reach the lacrimal gland. |
|
|
Term
| Where is the pterygopalantine fossa located? |
|
Definition
| The pterygopalatine fossa is located deep to the infratemporal fossa and posterior to the maxilla. |
|
|
Term
| Describe the course for the Parasympathetic fibers in the Facial Nerve that supply the Sublingual/Submandibular Glands |
|
Definition
| For the salivary glands, preganglionic parasympathetics travel in the facial nerve but then reach the submandibular ganglion via the chorda tympani and the lingual nerve. Post-ganglionic parasympathetics then travel to the glands either directly (submandibular gland) or via the lingual nerve (sublingual gland). |
|
|
Term
| Describe the course for the Vestibulocochlear Nerve (CN VIII) |
|
Definition
| Carries output from hair cells in the inner ear associated with hearing and balance. Enters the skull at the internal acoustic meatus. |
|
|
Term
| Describe which cranial nerves are involved in the gag reflex? |
|
Definition
The principal test of glossopharyngeal nerve function examines its role as the source of general sensation of the soft palate. In this respect it is the afferent limb of the gag (pharyngeal) reflex.
The Vagus provides the efferent limb of the gag reflex. Pharyngeal branches of the vagus nerve innervate both pharyngeal constrictors (superior, middle, inferior) and most longitudinal muscles of the pharynx (e.g. palatopharyngeus; elevates soft palate) and palatoglossus (elevates tongue). |
|
|
Term
| Describe the course of the parasympathetic fibers in glossopharyngeal that travel to the parotid gland |
|
Definition
| CN IX is also the source of parasympathetic innervation of the parotid gland, with pre-ganglionics carried by the tympanic nerve and then the lesser petrosal nerve to the otic ganglia and post-ganglionics carried by the auriculotemporal nerve, a branch of V3. |
|
|
Term
| What are two ways in which the vagus nerve can be tested? |
|
Definition
| CN X is also the principle source of innervation to the muscles of the larynx. This means that vagus nerve function can be evaluated on the basis of sound production (phonation) and swallowing (deglutition). |
|
|
Term
| What portion of the vagus nerve innervates the muscles of the larynx and how does this lead to phonation |
|
Definition
- Most of the intrinsic muscles of the larynx are innervated by the recurrent branch (laryngeal) of the vagus nerve.
- Intrinsic muscles of the larynx alter the tension of the (true) vocal folds, the rima glottidis |
|
|
Term
| Explain how the Recurrent Laryngeal Nerve course differs on the Left and Right side |
|
Definition
On Left side the vagus nerve passes all the way down to the inferior margin of the arch of the aorta and then gives rise to the Left Recurrent Pharyngeal Nerve
Right side goes down, loops under inferior margin of the R subclavian artery |
|
|
Term
| Describe how the Recurrent Branch of the Vagus nerve is also involved in swallowing |
|
Definition
-Recurrent branch also plays an important role in swallowing by providing innervation to intrinsic laryngeal muscles that close the vocal folds and the movements that cause the epiglottis to swing down, narrowing or close the laryngeal inlet.
- During this process the larynx is elevated with the pharynx under the posterior border of the tongue by muscles innervated by CN IX or X.
[Stylopharyngeus (IX), salpingopharyngeus (X), palatopharyngeus (X) and inferior constrictor (X).] |
|
|
Term
| Describe the course of the Spinal Accessory Nerve (CN XI) |
|
Definition
| Innervates sternocleidomastoid and trapezius. The origin of this nerve are fibres from upper cervical spinal cord that enter the skull through the foramen magnum but then exit through the jugular foramen. |
|
|
Term
| Describe the course of the Hypoglossal Nerve (CN XII) |
|
Definition
| Hypoglossal nerve. Exits the skull through the hypoglossal canal. All muscles of the tongue (except palatoglossus, CN X). |
|
|
Term
| Describe how sensation is carried from the tongue |
|
Definition
Note that taste from the posterior 2/3 of the tongue is carried by CN IX.
General sensation is carried by CN V3 (anterior 1/3) and CN IX (posterior 2/3). |
|
|
Term
| Lecture: Brainstem Anatomy |
|
Definition
|
|
Term
| Name the Gross Anatomical Features of the Medulla Oblongata |
|
Definition
1. Pyramidal tracts and Decussation of the pyramids
2. Fasciculus and nucleus gracilis, fasciculus and nucleus cuneatus
3. Olive
4. Inferior cerebellar peduncle
5. Hypoglossal and vagal trigones
6. CN XII (hypoglossal nerve), CN XI (spinal accessory nerve), CN X (vagus nerve), CN IX
(glossopharyngeal nerve) |
|
|
Term
| Why are the pyramids called the pyramids? |
|
Definition
| The cells in the cerebral cortex giving rise to axons that comprise these tracts are pyramidal in shape |
|
|
Term
| Describe the Decussation of the Pyramids at the Medulla |
|
Definition
| Occurs at the caudal medulla. As you descend on ventral surface of the medulla, the ventral median fissure is occluded by fibers crossing, crossed fibers continue down the cord as lateral corticospinal tract and a few uncrossed fibers continue as the uncrossed ventral corticospinal tract |
|
|
Term
| What divides the OPEN and CLOSED Medulla |
|
Definition
| Where the 4th ventricle opens the upper surface of the medulla |
|
|
Term
| What information are the fasiculus gracilis and cuneatus carrying? |
|
Definition
| Fine touch, proprioception, vibration |
|
|
Term
| The nucleus gracilis is more (caudal or rostral) and more (medial/lateral) than the nucleus cuneatus |
|
Definition
|
|
Term
| What is the function of the Inferior Olive |
|
Definition
| It's a nicleus that receives information from a wide variety of CNS regions and ships it to the cerebellum via the Inferior Cerebellar Peduncle |
|
|
Term
| T or F: the Inferior Cerebellar Peduncle is comprised only of Olivary-Cerebellar fibres |
|
Definition
| False, but most of it is comprised of them! |
|
|
Term
| What are the hypoglossal and vagal trigones? |
|
Definition
| Surface representations of the hypoglossal nuclei and one of the nuclei for the vagas (dorsal motor nucleus) |
|
|
Term
| Which is more rostral, the hypoglossal or vagal trigone? |
|
Definition
| Hypoglossal nerve trigone |
|
|
Term
| Where does the Glossopharngeal nerve exit the brainstem |
|
Definition
| Arises above the olive at the interface between the medulla and the pons |
|
|
Term
| Why is the XI cranial nerve called Spinal Accessory? |
|
Definition
| Accessory is because it carries some fibers derived from 10th nerve nuclei; spinal part is because fibers arise from upper portions of the cervical spine which come in through foramen magnum and then go out jugular along with 9 and 10 to be distributed to the SCM and Trapezius muscles |
|
|
Term
| Name the Gross Anatomical Features of the Pons |
|
Definition
1. Basilar pons - Transverse fibers; middle cerebellar peduncle
2. Facial colliculus
3. Vestibular area
4. CN VIII (vestibulo-cochlear), CN VII (facial), CN VI (abducens), CN V (trigeminal) |
|
|
Term
| The middle cerebellar peduncle consists exclusively of what? |
|
Definition
| Incoming info derived ultimately from cortical sources |
|
|
Term
| T or F: The transverse fibers of the basilar pons are directly connected to the cortex |
|
Definition
| False, they arise from neurons that receive cortical input |
|
|
Term
| The Facial colliculus is the surface representation of what? |
|
Definition
| Arching colleciton of fibers derived from facial motor nucleus (not a nucleus itself but fibers that buldge up into the floor of the fourth ventricle), immediately beneath that is a nucleus associated with the 6th nerve |
|
|
Term
| What lies lateral to the facial colliculus? |
|
Definition
| Vestibular area, beneath which lies the vestibular nuclei associated with that portion of the 8th nerve |
|
|
Term
| What separates the facial colliculus and the vestibular area |
|
Definition
| The sulcus limitans note (motor structures are medial and sensory are lateral to the sulcus limitans) |
|
|
Term
| What are the 3 divisions of the trigeminal nerve |
|
Definition
| Opthalamic, Maxillary, Mandibular |
|
|
Term
| Name the Gross Anatomical Features of the Midbrain |
|
Definition
1. Basis pedunculi - Composition
2. Interpeduncular fossa
3. Corpora quadrigemina
a. Superior colliculus
b. Inferior colliculus
4. Superior cerebellar peduncle
5. CN IV (trochlear), CN III (oculomotor) |
|
|
Term
| Name two fiber types that go through the Basis Pedunculi |
|
Definition
| Corticospinal (continuation of the pyramids) and corticopontine |
|
|
Term
| What is located between the two basis pedunculis |
|
Definition
| The interpeduncular fossa at the bottom of which is the posterior perforated substance |
|
|
Term
| What is the function of the Posterior Perforated Substance? |
|
Definition
| It's where perforating/ganglionic arteries penetrate the brain, especially the posterior medial group |
|
|
Term
| Describe the Function of the Superior Colliculus |
|
Definition
| Superior colliculus takes visual information from variety of sources including retina and cortex but not considered a sensory nucleus in terms of processing information that one consciously perceives; rather it takes visual information and ships it off to a variety of motor centres; purpose to coordinate head and eye movements based on visual input |
|
|
Term
| Describe the Function of the Inferior Colliculus |
|
Definition
| Inferior colliculus is a nucleus interposed on auditory pathway, takes incoming auditory information and passing it along to higher centers for conscious perception of sound |
|
|
Term
| What is the general function of the Superior Cerebellar Peduncle |
|
Definition
| Superior Cerebellar peduncle connects with the midbrain and conveys information processed in the cerebellum outward to be distributed to appropriate motor centres on which the cerebellum must exert control |
|
|
Term
| Describe the course of the Trochlear and Occulomotor Nerves |
|
Definition
| below the inferior colliculus is the trochlear nerve which wraps itself around the basis pedunculi and joins with the occulomotor nerve which arises from the interpeduncular fossa medial to the basis pedunculi, both of which exit cranial cavity by the Superior Orbital Fissure |
|
|
Term
| Name the nuclei associated with Cranial Nerve III and include the type of nucleus |
|
Definition
Oculomotor Nucleus (Somatic Motor)
Edinger-Westphal Nucleus (Visceral Motor) |
|
|
Term
| Re-name the functions of CN III and which nuclei correspond |
|
Definition
OCULOMOTOR NUCLEUS:
Somatic Motor (GSE): Innervates Superior, Medial and Inferior Rectus, Inferior Oblique and Levator palpebrae
EDINGER-WESTPHAL NUCLEUS
Visceral Motor (GVE): Parasympathetic to ciliary and pupillary constrictor muscles |
|
|
Term
| Name the nuclei associated with Cranial Nerve IV and include the type of nucleus |
|
Definition
| Trochlear Nucleus (Somatic Motor) |
|
|
Term
| Re-name the functions of CN IV and which nuclei correspond |
|
Definition
TROCHLEAR NUCLEUS
Somatic Motor (GSE): Superior oblique muscle |
|
|
Term
| Name the nuclei associated with Cranial Nerve V and include the type of nucleus |
|
Definition
Spinal Nucleus (and tract) of the Trigeminal (Somatic Sensory)
Principle Sensory Nucleus of the Trigeminal (Somatic Sensory)
Mesencephalic nucleus of the Trigeminal (Somatic Sensory)
Motor Nucleus of the Trigeminal (Branchial Motor) |
|
|
Term
| Re-name the functions of CN V and which nuclei correspond |
|
Definition
MOTOR NUCLEUS OF TRIGEMINAL
Brachial Motor (SVE): Muscles of mastication
VARIOUS SENSORY NUCLEI (see next slide)
General Sensory (GSA): Sensory for the Anterior Head/Neck i.e. Face Mask Area |
|
|
Term
| What type of information do each the 3 sensory nuclei of the trigeminal each convey |
|
Definition
Principle Sensory= fine or discriminative touch
Mesencephalic= proprioception
Spinal= pain and temp |
|
|
Term
| Name the nuclei associated with Cranial Nerve VI and include the type of nucleus |
|
Definition
| Abducens Nuclei (Somatic Motor) |
|
|
Term
| Re-name the functions of CN VI and which nuclei correspond |
|
Definition
ABDUCENS NUCLEI
Somatic Motor (GSE): Lateral Rectus |
|
|
Term
| Name the nuclei associated with Cranial Nerve VII and include the type of nucleus |
|
Definition
Facial Nucleus (Branchial Motor)
Superior Salivary Nucleus (Visceral Motor)
Nucleus Solitarius (Visceral Sensory)
Sensory Nucleus of V (Somatic Sensory) |
|
|
Term
| Re-name the functions of CN VII and which nuclei correspond |
|
Definition
FACIAL NUCLEUS
Brachial Motor (SVE): Muscles of Facial Expression, Stapedius
SUPERIOR SALIVARY NUCLEUS
Visceral Motor (GVE): parasympathetic to lacrimal gland via the pterygopalantine ganglia, and submandibular/sunlingual glands through the Submandibular ganglia
SENSORY NUCLEUS OF V
General Sensory (GSA): external ear
NUCLEUS SOLITARIUS
Special Sensory (SVA): taste for anterior 2/3 of tongue |
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Term
| Name the nuclei associated with Cranial Nerve VIII and include the type of nucleus |
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Definition
| Vestibular nuclei (superior, inferior, medial, lateral) and Cochlear nuclei (dorsal, ventral) = Special Sensory |
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Term
| Re-name the functions of CN VIII and which nuclei correspond |
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Definition
Vestibular nuclei (superior, inferior, medial, lateral) and Cochlear nuclei (dorsal, ventral)
Special Sensory (SSA): hearing and balance |
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Term
| Name the nuclei associated with Cranial Nerve IX and include the type of nucleus |
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Definition
Nucleus ambiguous (Branchial Motor)
Inferior Salivary Nucleus (Visceral Motor)
Nucleus Solitarius (Visceral Sensory)
Sensory Nucleus of V (Somatic Sensory) |
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Term
| Re-name the functions of CN IX and which nuclei correspond |
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Definition
Nucleus ambiguous
Brachial Motor (SVE): stylopharyngeus- swallowing)
Inferior Salivary Nucleus
Visceral Motor (GVE): to parotid gland via the otic ganglion
Nucleus Solitarius
Special Sensory (SVA): taste for posterior 1/3 of tongue, pharynx, carotid body and sinus, aortic arch
Sensory Nucleus of V
Somatic Sensory (GSA/GVA): external ear, general sensation for posterior one-third of the tongue
Inferior Salivary Nucleus (Visceral Motor)
Nucleus Solitarius (Visceral Sensory)
Sensory Nucleus of V (Somatic Sensory) |
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Term
| Name the nuclei associated with Cranial Nerve X and include the type of nucleus |
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Definition
Nucleus Ambiguous (Branchial Motor)
Dorsal Motor Nucleus of the Vagus (Visceral Motor)
Nucleus Solitarius (Visceral Sensory)
Sensory Nucleus of V (Somatic Sensory |
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Term
| Re-name the functions of CN X and which nuclei correspond |
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Definition
Nucleus Ambiguous
Branchial Motor (SVE): pharynx-swallowing, larynx, levator veli palantini
Dorsal Motor Nucleus of the Vagus
Visceral Motor (GVE): parasympathetics thorax and abdominal viscera as far as the transverse colon
Nucleus Solitarius
Visceral Sensory (SVA, GVA): epiglottis-taste, pharynx, larynx, trachea, esophagus and thoracic and abdominal viscera
Sensory Nucleus of V
Somatic Sensory (GSA): external ear |
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Term
| Name the nuclei associated with Cranial Nerve XI and include the type of nucleus |
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Definition
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Term
| Re-name the functions of CN XI and which nuclei correspond |
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Definition
Accessory Nucleus
Branchial Motor (GSE): to SCM and Trapezius |
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Term
| Name the nuclei associated with Cranial Nerve XII and include the type of nucleus |
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Definition
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Term
| Re-name the functions of CN XII and which nuclei correspond |
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Definition
Hypoglossal Nucleus
Somatic Motor (GSE): Intrinsic and Extrinsic Muscles of the Tongue except Palatoglossus (CN X) |
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Term
| What Pathways are found in the Medulla Oblongata |
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Definition
Continuation of the Corticospinal Tract:
1. Pyramids and decussation of the pyramids
Continuation of the Dorsal Column-Medial Leminiscus System
2. Fasciculus gracilis and cuneatus; nucleus
gracilis and cuneatus
3. Internal arcuate fibers and sensory decussation
4. Medial lemniscus |
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Term
| Name the Cranial Nerve Related Structures Found in the Medulla Oblongata |
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Definition
1. Elements of cranial nerves related to motor function
a. CN XII: Hypoglossal nucleus
b. CN X: Dorsal motor nucleus of the vagus nerve
c. CN IX and X: Nucleus ambiguus
d. CN IX: Inferior Salivary Nucleus
2. Elements of cranial nerves related to sensory function
a. CN VII, IX and X: Solitary tract and nucleus
b. CN V (and VII, IX, X): Spinal tract and nucleus of the
trigeminal nerve
c. CN VIII: Medial and inferior vestibular nuclei, MLF
Dorsal and ventral cochlear nuclei |
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Term
| Name the Cerebellum Related Structures Found in the Medulal Oblongata |
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Definition
1. Lateral cuneate nucleus
2. Inferior olivary nucleus (Principal nucleus,
dorsal and medial accessory olivary nuclei 3. Olivocerebellar fibers
4. Inferior cerebellar peduncle: Restiform and juxtarestiform bodies |
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Term
| What other structure comprises a significant portion of the Medulla Oblongata |
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Definition
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Term
| Describe the Internal Arcuate Fibers |
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Definition
| Neurons in both the nuclei give off axons that sweep ventrally and medially to form what is known as the internal arcuate fibers= internal because deep within medulla and arcuate because they arch toward midline; at midline they undergo a decussation, then form a tract on either side of the midline of crossed fibers known as the medial leminiscus; this tract persists as we ascend through the brainstem |
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Term
| How are the fibers in the Medial Leminiscus Organized? |
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Definition
| Medial Leminiscus is somatotopically organized such that fibers that convey information from the neck region are up toward the top of the tract, then arm, then trunk then leg as you move more ventrally |
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Term
| Where are the fibers of the Antero Lateral Tract (Lateral Spinothalamic Tract) located in the Medulla? |
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Definition
| At this point in the brainstem the fibers of the AnteroLateral system (Lateral Spinothalamic Tract which contains pain and temp) are too diffusely organized to point to a tract |
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Term
| Hypoglossal Nucleus: location, function and course of the nerve |
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Definition
a. Located beneath hypoglossal trigone
b. Motor nucleus for intrinsic and extrinsic muscles of the tongue
c. Large alpha motor neurons give rise to axons forming CN XII, exit between inferior olivary nucleus and pyramids |
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Term
| Dorsal Motor Nucleus of the Vagus: location and function |
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Definition
a. Located beneath vagal trigone
b. Consists of parasympathetic, preganglionic neurons contributing to CN X |
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Term
| T or F: the neurons in the dorsal motor nucleus of the vagus are smaller than those in the hypoglossal nucleus |
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Definition
| True, this is typical of autonomic neurons generally |
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Term
| Describe the location and role of the Nucleus Ambiguous |
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Definition
- Branchial Motor Nucleus
- Group of motor neurons located in “center” of medulla
- Provides motor innervation to stylopharyngeus muscle (CN IX), to palatine, pharyngeal, and laryngeal muscles, and to striated muscles of upper 1/3rd of esophagus i.e. IMPORTANT for SPEECH and SWALLOWING
- Parasympathetic, preganglionic outflow to the heart (CN X) |
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Term
| Tractus and nucleus solitarius |
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Definition
- Tract consists of fibers (axons) derived from CN VII (facial), CN IX (glossopharyngeal) and CN X (vagus) nerves; descends throughout medulla
- Nucleus surrounds tract
- Input from CN VII conveys sensation of taste from anterior 2/3s of the tongue; input from CN IX conveys sensation of taste from posterior 1/3 of the tongue and chemoreceptor input from carotid body; CN X convey baroreceptor input from aortic body and general visceral sensation from viscera of thorax and abdomen |
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Term
| How is it that the Nucleus Soltarius in the Medulla but receives input from CN VII which is associated with the Pons? |
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Definition
| Ganglion axons associated with the geniculate ganglion of CN VII (Facial) and Inferior ganglion of IX and X come in to the brainstem and then turn caudally and run down the length of the medulla; so you see the tractus solitarius for the length of the medulla; from raustral end is where 7 comes in and later on 9 and 10 |
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Term
| Describe the two portions of the Nucleus Solitarius |
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Definition
Facial nerve has a sensory component that conveys taste from the anterior 2/3rds of the tongue (these are incoming taste fibers); joined by incoming taste fibers from the Glossopharyngeal (1/3 of the tongue) forming the gustatory portion of the nucleus solitarius (afferent sensory info that will be passed along to second order neurons for taste in roughly upper third of nucleus solitarius)
9 and 10 also convey information derived from the viscera; both chemo and baro-receptors and also general visceral sensation with exception of pain; for 10 this means distention movement etc; this sort of information is distributed roughly to the caudal 2/3rds of the nucleus solitarius |
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Term
| Spinal tract and nucleus of the trigeminal nerve function |
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Definition
- All Pain and Temperature Information
- Spinal tract extends from pons to upper level of spinal cord
- Consists of sensory fibers derived from CN V, VII, IX and X
- Fibers (axons) terminate in spinal nucleus of CN V
- Involved with pain and temperature sensation from face, teeth, mouth, and tongue, as well as portions of ear, pharynx, larynx, esophagus |
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Term
| Describe the Structures associated with vestibulocochlear nerve (CN VIII) seen in the Medulla |
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Definition
-Two of Four vestibular nuclei (Medial and Inferior) located beneath vestibular area in floor of fourth ventricle
- Two cochlear nuclei (dorsal, ventral) located adjacent to inferior cerebellar peduncle
- Ascending medial longitudinal fasciculus (MLF) consists in part of fibers (axons) from neurons in vestibular nuclei, projecting to motor nuclei (CN III, IV, and VI) innervating extraocular muscles |
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Term
| Why can we see vestibulochoclear structures in the medulla when it's suppose to be associated with the pons? |
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Definition
| The Vestibulocochlear nerve enters brainstem at junction between the medulla and the pons (far laterally), has a large number of central components some of which do appear at the level of the medulla at the very far raustral medulla |
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Term
| What is the function of the Lateral Cuneate Nucleus |
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Definition
- Lateral cuneate nucleus receives input via collaterals of fasciculus cuneatus, projects to cerebellum to provide proprioceptive information for upper limb
- Found medially adjacent to the inferior cerebellar peduncles
- Recall that one of the sources of input to the cerebellum via the dorsol spino-cerebellar tract was the thoracic nucleus (Clarke’s column at posterior horn of the spinal cord) but this is only found from T1-L2 for the lower limb sand trunks so the lateral cuneate nucleus is the equivalent for the upper limbs |
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Term
| Describe the composition and function of the Inferior Olivary Nuclear Group |
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Definition
- Components: Dorsal accessory, medial accessory, and principal olivary nuclei
- Receives wide ranging input from cortex, midbrain, spinal cord
- Olivo-Cerebellar Fibers cross midline and enter the cerebellum via the inferior cerebellar peduncle |
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Term
| Describe the function and composition of the Inferior Cerebellar Peduncle |
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Definition
a. Consists of fibers mainly, but not exclusively, afferent (incoming) to the cerebellum
b. Comprises the larger restiform body and smaller medially located justarestiform body |
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Term
| What Major Pathways are found in the Pons |
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Definition
1. Corticospinal tracts
2. Medial lemniscus
3. Spinal lemniscus |
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Term
| What Cranial Nerve Related Structures are Featured in the Pons |
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Definition
1. Elements of cranial nerves related to motor function
a. CN VII: Facial nucleus, Genu and fibers of facial nerve, Superior Salivary Nucleus
b. CN VI: Abducens nucleus, Fibers of abducens nerve
c. CN V: Motor nucleus of the trigeminal nerve
2. Elements of cranial nerves related to sensory function
a. CN VIII: Superior and lateral vestibular nuclei Medial longitudinal fasciculus, Trapezoid body, Superior olive
b. CN V: Spinal tract and nucleus of trigeminal nerve
Principal sensory nucleus of the trigeminal nerve Mesencephalic tract and nucleus of the trigeminal nerve |
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Term
| Cerebellar Related Structures associated with the Pons |
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Definition
1. Corticopontine fibers
2. Pontine nuclei
3. Transverse fibers of the pons
4. Middle cerebellar peduncle
5. Inferior and superior cerebellar peduncle |
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Term
| What other structure comprises a significant portion of the Pons |
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Definition
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Term
| The Pons is divided into what two regions |
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Definition
Tegmentum:Dorsal region of the pons, found immediately beneath fourth ventricle. Includes cranial nerve related structures, sensory pathways, reticular formation
Basilar Pons: Includes motor pathways like the corticospinal tracts, some cerebellar related structures |
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Term
| Why is it uncommon to see obvious damage to the ventral corticospinal tract pathologically? |
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Definition
| Don’t see degeneration at ventral corticospinal tract because only 15% of fibers descend ipsilaterally; might expect to see it on the same side as the pyramids except that the ventral tract doesn’t go much past the cervical cord so don’t see any anterior degeneration |
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Term
| How does the Medial Leminiscus change in the Pons compared to the Medulla? |
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Definition
- Longitudinally coursing fibers arranged in oblong bundle oriented parallel to border between tegmentum and basilar pons; fibers still somatotopically organized
- Fibers trending out laterally so they can eventually meet the thalamus |
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Term
| What is the Spinal Leminiscus |
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Definition
| Consists of spinothalamic fibers located at lateral margin of medial lemniscus (note: haven’t seen them lower down that this because they weren’t aggregated into a neat bundle under this point) |
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Term
| What structures are associated with vestibulo-cochlear nerve (CN VIII) are in the Pons |
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Definition
a. Superior and lateral vestibular nuclei (two of a total of four vestibular nuclei) are located laterally in caudal pons
b. Medial longitudinal fasciculus (MLF) consists chiefly of ascending fibers from vestibular nuclei;terminate in nuclei of CN VI, IV, and III and cervical spinal nuclei
c. Trapezoid body consists of crossing axons related to auditory pathway; implies central pathway for hearing is crossed and uncrossed
d. Superior Olive: nucleus, unrelated to inferior olive; this one is inserted along the cochlear pathway |
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Term
| What Structures associated with facial nerve (CN VII) are in the Pons and where the nerve exits |
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Definition
- Motor nucleus of facial nerve located ventrolaterally in pontine tegmentum; supplies muscles of facial expression, a number of other muscles
- Collection of LMNs
- Genu of the facial nerve consists of the axons of neurons in facial nucleus that arch over abducens nucleus and form the facial colliculus
- Nerve exits from the surface of the pons out laterally, just medially adjacent to eight |
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Term
| Structures associated with the abducens nerve (CN VI) in the Pons including where the nerve exits |
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Definition
a. Abducens nucleus located adjacent to dorsal midline in tegmentum
b. Axons sweep ventrally, exit at ponto-medullary junction; supply lateral rectus muscle |
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Term
| Structures associated with the Trigeminal nerve (CN V) in the Pons |
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Definition
a. Spinal tract and nucleus of trigeminal extends from pons, through medulla, into upper cervical cord; mediates pain and temperature information
b. Principal (or main) sensory nucleus of trigeminal located in lateral tegmentum at mid-pons level;mediates sensations of fine, discriminative touch
c. Motor nucleus of trigeminal located medially adjacent to principal sensory nucleus; supplies motor innervation to muscles of mastication and a number of other muscles
d. Mesencephalic tract ascends through dorsolateral pons, consists of axons of pseudounipolar neurons comprising the mesencephalic nucleus in caudal mesencephalon; mediates information related to proprioception |
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Term
| What is the purpose of proprioceptive information from the face? |
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Definition
| In order to adjust force of bite you need to know occlusion of lower jaw to upper jaw therefore position of the jaw and know the degree of contraction |
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Term
| T or F: The pseudounipolar cells of the Mesencephalic Nucleus of the Trigeminal are the only pseudounipolar cells found in the CNS |
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Definition
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Term
| T or F: all the fibers comprising the Trigeminal Nerve go through the Trigeminal Ganglion before entering their various nuclei |
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Definition
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Term
| Describe the Corticopontine Tracts in the Pons |
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Definition
Corticopontine tracts
a. Cell bodies of origin for tracts mainly located in frontal cortex, but other cortical regions contribute
b. Descend through internal capsule, basis pedunculi to end on pontine nuclei in basilar pons |
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Term
| Describe the Pontine Nuclei in the Pons |
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Definition
Pontine nuclei
a. Scattered nuclear groups found throughout basilar pontine region
b. Receive input from corticopontine fibers |
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Term
| Describe the Transverse Fibers found in the Pons as well as the Peduncles seen here |
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Definition
3. Transverse fibers of pons and middle cerebellar peduncle
a. Transverse fibers arise from pontine nuclei, cross basilar pons, enter cerebellum via middle
cerebellar peduncle; completes cortico-ponto-cerebellar pathway
b. Inferior and superior cerebellar peduncles located medial to fibers comprising middle peduncle |
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Term
| T or F: At the level of the pons you can only see the Superior and Middle Cerebelar Peduncle |
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Definition
| False you can see all three at the rostral pons! |
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Term
| Describe the 4 Portions of the Mesencephalon |
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Definition
1. TECTUM – Includes the corpora quadrigemina, the region dorsal to the cerebral aqueduct
2. TEGMENTUM – Analogous to the tegmentum of the pons
3. SUBSTANTIA NIGRA – A motor nucleus ventral to the tegmentum
4. BASIS PEDUNCULI (or Crus Cerebri)– The large ventrally located fiber bundle which includes the corticospinal, corticobulbar, and corticopontine tracts |
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Term
| Define the Cerebral Peduncle |
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Definition
| CEREBRAL PEDUNCLE includes the tegmentum, substantia nigra and the basis pedunculi |
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Term
| What Pathways are seen in the Mesencephalon |
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Definition
1. Corticospinal and corticopontine tracts
2. Medial lemniscus and spinal lemniscus |
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Term
| What Cranial Nerves Related Structures are seen in the Mesencephalon |
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Definition
1. Elements of cranial nerves related to motor function
a. CN IV: Trochlear nucleus Trochlear nerve fibers
b. CN III: Oculomotor nucleus
Nucleus of Edinger-Westphal
2. Elements of cranial nerves related to sensory function
- CN VIII: Inferior colliculus Lateral lemniscus
Medial longitudinal fasciculus
- CN II: Superior colliculus
- CN V: mesencephalic nucleus of 5 (sensory)
Tectobulbar and tectospinal tracts |
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Term
| What Cerebellar Related Structures are seen in the Mesencephalon |
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Definition
1. Superior cerebellar peduncle
2. Decussation of superior cerebellar peduncle
3. Red nucleus, parvocellular portion |
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Term
| What other significant Structures are seen in the Mesencephalon |
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Definition
Substantia Nigra: pars compacta and pars reticulata
Reticular Formation |
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Term
| Where are the Corticospinal Tracts located in the Mesencephalon |
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Definition
| Descend through basis pedunculi; occupies middle 3/5ths of this region; somototopically organized |
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Term
| Where are the medial and spinal leminiscus found in the mesencephalon |
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Definition
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Term
| What structures are associated with the vestibulo-cochlear nerve in the Mesencephalon? |
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Definition
a. Lateral lemniscus a part of the auditory pathway; terminates in the inferior colliculus, a nucleus along auditory pathway
b. Inferior colliculus projects via brachium to medial geniculate body of thalamus
c. Medial longitudinal fasciculus (MLF) a rostral continuation of tract seen in pons; terminates in the nuclei of trochlear nerve (CN IV) and oculomotor nerve (CN III) |
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Term
| Structures associated with Trochlear nucleus and fibers (CN IV) in the Mesencephalon |
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Definition
| Nucleus located at level of inferior colliculus, gives rise to fibers (axons) that arch around PAG (Periaquatal grey around the cerebral aquaduct) and exit dorsally on brainstem; innervates superior oblique muscle of eye |
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Term
| Structures associated with Oculomotor nucleus and fibers (CN III) in the Mesencephalon including where the nerve exits |
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Definition
a. Nucleus located at level of superior colliculus adjacent to the MLF, fibers exit on ventral surface at interpeduncular fossa between the two basis pedunculi
b. Includes motor nuclei for inferior oblique; superior, medial, and inferior recti muscles
c. Nucleus of Edinger-Westphal a parasympathetic nucleus innervating ciliary and constrictor pupillae muscles |
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Term
| Describe the function of the Superior Colliculus |
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Definition
- Superior colliculus receives visual input from a variety of sources
- Gives rise to tectospinal tract which projects to ventral horn motor neurons in cervical cord and
tectobulbar tract providing indirect input to nuclei of CN III, CN IV, and CN VI
Note: tecto because they arise form the tectum, bulbar means brainstem |
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Term
| Describe the location of the Corticopontine Fibers in the Mesencephalon |
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Definition
a. Descend through medial 1/5th and lateral 1/5th of basis pedunculi
b. Arise from motor cortex, but also from other cortical regions |
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Term
| Describe the Superior Cerebellar Peduncle |
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Definition
a. Consists mainly, but not exclusively, of fibers efferent from (leaving) the cerebellum
b. Decussation of the Cerebellar Peduncles at level of lower mesencephalon |
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Term
| Descrine the lovation and function Red Nucleus |
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Definition
a. Large motor nucleus extending roughly throughout rostral ½ of midbrain
b. Consists of magnocellular and parvocellular regions
c. Input derived from cerebral cortex and cerebellum
d. Projections from magnocellular division to spinal cord, from parvocellular division to inferior olivary nucleus
e. Named because in fresh material it’s heavily invested with capillaries so looks pink |
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Term
| Define the Substantia Nigra |
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Definition
| Large motor nucleus extending throughout length of mesencephalon; located between tegmentum and basis pedunculi |
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Term
| What are the two components of the Substantia Nigra? |
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Definition
| A Dorsal pars compacta and a Ventral pars reticulata |
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Term
| Describe the function of the Pars Compacta |
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Definition
Pars compacta contains pigmented neurons; melanin formed as a byproduct of metabolism of dopamine; Parkinsonism associated with degeneration of neurons in pars compacta
A motor nucleus connected to corpus striatum of forebrain; classified as one of the basal ganglia |
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Term
| Describe the function of the Pars Reticulata |
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Definition
| Contains Gabinergic neurons also involved with basal ganglia circuitry |
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Term
| Define the 3 Components of the Reticular Formation |
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Definition
1. Reticular formation of the central core region of the brainstem (the tegmentum at some levels) corresponds to the 2. The raphe nuclei located adjacent to midline of the stem
3. The locus ceruleus found in dorsolateral region of rostral pons and caudal midbrain |
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Term
| What are the Anatomical Components of the Reticular Formation |
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Definition
1. Nuclei in the central core of the stem
2. Raphe nuclei
3. Locus Ceruleus |
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Term
| What are the Nuclei in the central core of the stem for each of the brainstem components |
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Definition
In medulla: Ventral reticular nucleus, gigantocellular reticular nucleus
In pons: Caudal pontine reticular nucleus, rostral pontine reticular nucleus
In mesencephalon: Mesencephalic reticular nucleus |
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Term
|
Definition
| Group of nuclei located immediately adjacent to midline of stem throughout its length. Contains serotoninergic (5-HT) neurons. |
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Term
| Define the Locus Ceruleus |
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Definition
| Nucleus in the pons closely adjacent to mesencephalic nucleus of trigeminal. Consists of nor-adrenergic neurons giving rise to very widespread projections. They are deeply pigmented. Principal site for brain synthesis of norepinephrine |
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Term
| Functions mediated by medullary and pontine reticular nuclei |
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Definition
- Give rise to reticulobulbar and reticulospinal projections
- Influences somatic motor activity: Complex patterned movements, reflexes (inhibiting flexor reflexes)
- Influences visceral activity: Heart rate, blood pressure, respiratory movements
- Mediates sensory information: Pain and temperature sensations transmitted by spinoreticular fibers; these terminate in brainstem reticular formation, which projects to intralaminar thalamic nuclei, that in turn project to widespread regions of cerebral cortex |
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Term
| Functions mediated by raphe nuclei |
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Definition
- Input to raphe nuclei derived from periaqueductal gray of midbrain
- Raphe nuclei (nucleus raphe magnus) gives rise to 5-HT projection to dorsal horn of spinal cord, which influences transmission of pain sensations (this is an example of alternative pain pathway; less discrimination but wider distribution) |
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Term
| Functions mediated by midbrain reticular formation and locus ceruleus |
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Definition
- Activation of midbrain reticular formation by sensory inputs influences levels of arousal and alertness
- Reticular projections to locus ceruleus, which in turn gives rise to nor-adrenergic projections directly to cortex, influences sleep-wakefulness cycles
- Part of the Reticular Activating System; involved in levels of consciousness |
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|
Term
| Lecture: Aud/Vis Pathways |
|
Definition
|
|
Term
|
Definition
| It's the auditory portion of the inner ear located in the petrous temporal bone that consists of a spiral labyrinth wrapped around a central pillar, the modiolus |
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Term
| What are the three chambers of the cochlea and what substance is found in each |
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Definition
Scala vestibuli (perilymph)
Scala tympani (perilymph)
Cochlear duct or scala media (endolymph) |
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Term
| The scala vestibuli opens at the ____ and the scala tympani opens at the ____ |
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Definition
| The scala vestibuli opens at the ROUND WINDOW (which opens into the middle ear) and the scala tympani opens at the OVAL WINDOW (which receives the foot plate of the stapes) |
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Term
| T or F: the Scala vestibuli and Scala tympani are connected |
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Definition
| True, they are connected at the top of the spiral of the tube wound around the modiolus; they are seperated everywhere else by the scala media (cochlear duct) |
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Term
| What happens when the footplate of the stapes vibrates over the oval window? |
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Definition
| It induces a pressure wave in the perilymph which is transferred to the endolymph in the cochlear duct |
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Term
| The Cochlear duct is enclosed within what two membranes? |
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Definition
| The basilar membrane and vestibular membrane |
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Term
| What is found on the basilar membrane? |
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Definition
|
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Term
| The basilar membrane is found between what two chambers |
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Definition
| The cochlear duct and the scala tympani |
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Term
| Define the Organ of Corti |
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Definition
| It's the receptive organ for hearing; consists of inner and outer hair cells with stereocilia; this strip of epithelial cells allows for transduction of auditory signals into nerve impulses' action potential. |
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Term
| The stereocillia of the outer hair cells are located where? What about the inner hair cells? |
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Definition
| Stereocilia of outer hair cells insert into tectorial membrane; stereocilia of inner hair cells extend into endolymph |
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Term
| Describe the Steps in Hearing up until the Central Pathways |
|
Definition
- Process of hearing initiated when your tympanic membrane (lateral margin of inner ear) vibrates in relation to incoming auditory waves i.e. pressure waves
- Translated through three osicles: malleus, incus, stapes (across the middle ear)
- Footplate of the stapes vibrates on the oval window and send a pressure wave into the perilymph
- Fluid is incompressible so the round window bows in and out
- Wave transferred to the endolymph in the cochlear duct which perturbs the stereocilia arises from the apical surface of the hair cells comprising the Organ of Corti
- Physical movement of hair cells transduced into an electrical signal
- Base of the inner hair cells are contacted by the peripheral process of bipolar neurons, located in the spiral ganglion
- The central process of these bipolar neurons terminates in the dorsal and ventral cochlear nuclei |
|
|
Term
| What type of neuron are the first order neurons for the hearing pathway? |
|
Definition
| Bipolar typical of special sensory (remember in somatosensory pathways the first order neuron is pseudo-unipolar, these neurons too were originally biplor but the two axonal processes coalesce so they are pseudounipolar) |
|
|
Term
| Inner/Outer hair cells are responsible for most of the auditory information transmitted by the cochlear nerve |
|
Definition
|
|
Term
| Draw out the Central Auditory Pathway |
|
Definition
|
|
Term
| Describe basically in words the Central Auditory Pathway Steps |
|
Definition
a. Bipolar neurons in spiral ganglion contact bases of hair cells peripherally, project to cochlear nuclei centrally
b. Dorsal and ventral cochlear nuclei source of bilateral central auditory pathway
c. Crossed elements decussate via dorsal acoustic stria, intermediate acoustic stria, trapezoid body; synapses possible in superior olive ipsilaterally, contralaterally or both
d. Uncrossed element projects ipsilaterally to superior olive (nucleus)
e. Both crossed and uncrossed elements ascend in lateral lemniscus; possible synapse in nucleus of lateral lemniscus
f. Lateral lemniscal fibers terminate on neurons in nucleus of inferior colliculus
g. Neurons in inferior colliculus project to medial geniculate body (MGB) of thalamus via the brachium
h. MGB projects to auditory cortex in temporal lobe |
|
|
Term
| Regardless of which pathway the ventral cochlear neuron axons take, where do they all end up? |
|
Definition
| Whatever path they take once the fibers have crossed, regardless of if they come from cochlear nuclei directly or the superior olive, they aggregate to form the LATERAL LEMINISCUS; which ascends through the pons and into the caudal mesencephalon; there is a nucleus of the lateral leminiscus in which some of the axons may synapse and some of them may bypass |
|
|
Term
| Which synapse in the central auditory pathway is known as the obligate synapse and why? |
|
Definition
| Axons regardless of their origins, that comprise the lateral leminiscus terminate on the neurons forming the nucleus of the inferior colliculus; this synapse is known as an obligate synapse because it’s required along this pathway |
|
|
Term
| How are fibers organized in the primary auditory cortex |
|
Definition
| "TONOTOPICALLY” i.e. organized according to pitch with high tones medial and low tones lateral |
|
|
Term
| A patient presenting with total deafness in one ear would likely have a lesion where? |
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Definition
| In all likelihood the lesion producing that deficit is peripheral; either involving the Organ of Corti, or the peripheral nerve root |
|
|
Term
| A lesion in the central pathways would most likely cause what kind of hearing impairment |
|
Definition
- Once it gets to the brainstem because the pathways are crossed the lesion there will not give total deafness but rather a dimming of acuity of hearing in principally the crossed ear but NOT total deafnes
- Only way to get deafness from a central lesion is if both lateral leminiscus were interupted, the are on opposite side of the pons and caudal midbrain, you can imagine a lesion that size would affect many more important things than hearing |
|
|
Term
| What would a central lesion in the lateral leminiscus specially cause? |
|
Definition
| Inability to localized sound in space; has to do with all the intermediate nuclei connected with one another |
|
|
Term
| Name the two labyrinths that compose the vestibular apparatus |
|
Definition
| The kinetic labyrinth and the static labyrinth |
|
|
Term
| Describe the composition and general function of the kinetic labyrinth |
|
Definition
- Composed of the 3 semicircular canals (superior, posterior, horizontal) in mutually perpendicular planes with ampullae (enlargements at the ends of the semicircular canals) that house cristae which consist of hair cells
- Detects movement, angular acceleration (rotation)
- The canals and ampullae are filled with endolymph |
|
|
Term
| Describe the composition and general function of the static labyrinth |
|
Definition
- Consists of the saccule and the utricle which are filled with endolymoh and house the maculae which consists of hair cells
- Detects position and linear acceleration |
|
|
Term
| How is vestibular information detected in the semicircular canals? |
|
Definition
- Relative movement of fluid in the semicircular canals stimulates hair cells in the ampullae that are dilated at the end of the canals
- Hair cells here form an organ called the Organ of Cristia
- Stereocillia of these hair cells are embedded in a gelatinous mass called the Cupula which makes it susceptible to relative movement of the endolymph past that gelatinous mass that in turns perturbs the stereocillia |
|
|
Term
| How is vestibular information detected in the saccule and utricle? |
|
Definition
- The Saccule and Utricle house a collection of hair cells that make up an organ known as the Macula
- Saccule and Utricle detect position relative to gravity i.e. position in space but also detects linear acceleration, accomplished by insertion into the gelatinous mass that covers the hair cells of small concretions of calcium carbonate called otoconia, which imparts a certain degree of inertia and also responds to gravity as you stand still, that increases the mass of the investment of the sterocillia such that linear acceleration is detected when you move forward and there’s a slight lag in the movement of the gelatinous substance that perturbs hair cells |
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|
Term
| How does the movement of the hair cells get translated to central vestibular pathways? |
|
Definition
| - Like the cochlea, when hair cells stereocillia move, that movement is transduced into electrical signal that is picked up by the peripheral process of bipolar neurons in vestibular ganglia; same broad arragement as we saw in the cochlea but in this case the hair cells move with movement of the head |
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Term
| T or F: there is no single central pathway for vestibular projections |
|
Definition
| True, the neurons of the vestibular ganglia project centrally to terminate in each of 4 vestibular nuclei: superior, medial, inferior, lateral and output from these 4 is widely distributed |
|
|
Term
| Draw out the Central Vestibular Pathway |
|
Definition
|
|
Term
| Describe the Vestibular Projections to the Spinal Cord |
|
Definition
- Lateral vestibular nucleus gives rise to axons that descend through the brainstem and spinal cord all the way to the lower cord, called the Lateral Vestibular Spinal Tract which descends ipsilaterally; it brings information to LMNs in the ventral horn of the spinal cord at various levels about vestibular input and movement in order for your muscles to react to this information
- Medial vestibular nucleus gives rise to axons that descend both crossed and uncrossed in the descending component of the medial longitudinal fasiculus OR called the medial vestibulospinal tract; these fibers don’t go much further than cervical cord before they enter the ventral horn and influence activity of the ventral horn motor neurons largely indirectly through interneurons |
|
|
Term
| Describe the Vestibular Projections to the Cerebellum |
|
Definition
- The superior, medial and inferior nuclei project to the cerebellum; this is a case of the cerebellum (a motor structure) receiving info about movement which it needs in order to co-ordinate and synchronize movements
- Cerebellum sends fibers back to the vestibular nuclei from which it received information |
|
|
Term
| Describe the Vestibular Projections to the Brainstem |
|
Definition
- Ascending Medial Longitudinal Fasiculus which we’ve already seen (prominent pathway adj to midline that ascends through the medulla, pons and into mesecephalon) conveys vestibular information crossed and uncrossed to nuclei of CN III, IV and VI; nuclei whose axons provide motor innervation to extra-occular muscles
- Brainstem also gets some projections from the vestibular nuclei to ‘visceral centers’ these visceral centers are part of the Reticular Formation (remember reticular formation has affects on viscera) and its been suggested that this projection may be the explanation for some people subject to motion sickness |
|
|
Term
| Describe the Vestibular Projections to the Thalamus and Cortex |
|
Definition
| - Superior, Lateral and Inferior project to ventral posterolateral and posterior thalamic nuclei which in turn give rise to projections to somato-sensory cortex in face and hand regions of the primary sensory cortex (postcentral gyrus); reason you consciously perceive vestibular input |
|
|
Term
| What is the receptive organ for sight |
|
Definition
|
|
Term
| The Retina consists of how many cell layers and how many cell types |
|
Definition
| Ten layers and five cell types |
|
|
Term
| How many layers must light go through before it reaches the layer that detects the light |
|
Definition
| Has to go through 8 layers before it reaches the rods and cones= the detection layer; this is because of development, the retina is actually a direct outgrowth of the brain and arises from the diencephalon |
|
|
Term
| T or F: a lot of information processing actually occurs in the retina before it gets to the thalamus |
|
Definition
|
|
Term
| Describe the Pathway for vision up until the central pathway |
|
Definition
Direct neural pathway for sight originates in retina, where three of the cells associated with path are
located
a. Rods and cones the receptor cells; cones concentrated in macula lutea of fovea centralis
b. Rods and cones contacted by bipolar cells
c. Bipolar cells synapse on retinal ganglion cells
d. Axons of ganglion cells converge on optic papilla, leave eyeball |
|
|
Term
| What cell types are responsible for local circuitry processing in the retina? |
|
Definition
| - Some interneurons, horizontal cells and amarcrine cells involved in local circuit processing in retina note; a lot of retina processing is not accomplished by electric potentials but rather modulation of local circuits |
|
|
Term
| The Optic nerve is formed by axons of ____ |
|
Definition
|
|
Term
| The optic disc is also called the ___ |
|
Definition
|
|
Term
| What area of the eye has the most visual acuity? |
|
Definition
| The macula which contains the fovea |
|
|
Term
| What occurs at the optic chiasm? |
|
Definition
- Nerves converges on optic chiasma, where undergo a partial decussation
- Axons from ganglion cells located in nasal half of retina cross, those from temporal half remain uncrossed |
|
|
Term
| Describe what happens to the optic tract? |
|
Definition
| Optic tract, consisting of both crossed and uncrossed fibers, continues from chiasma to lateral geniculate body (LGB) of thalamus |
|
|
Term
| The Lateral Geniculate Body consists of __ layers |
|
Definition
|
|
Term
| Crossed fibers go to what layers in the LGB? What about uncrossed? |
|
Definition
| Crossed fibers distributed to layers 1, 4 and 6 of LGB; uncrossed fibers distributed to layers 2, 3 and 5 of LGB |
|
|
Term
| Where does the LGB project to? |
|
Definition
- LGB projects to visual cortex in occipital lobe via optic radiation (also known as the visual radiation or geniculocalcarine tract)
- Geniculocalcarine tract, including Meyer’s loop, projects to striate cortex (Brodmann’s area 17) on either side of calcarine fissure of occipital lobe |
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|
Term
| The visual pathway is a __ cell pathway |
|
Definition
| 4 cell pathway: rods/cones, bipolar cells, ganglion cells (all in retina) then LGB |
|
|
Term
|
Definition
| Geniculostriate pathway going to the cortex goes laterally and then back; it’s going outside the ventricular system; a collection of lower fibers (physically lower) goes down into the temporal lobe to go around the inferior horn of the lateral ventricle and then comes back; this is called Meyer’s loop (arrangement is the same as the others but location distinguishes it) |
|
|
Term
| Describe how the Visual Field is organized in the primary visual cortex |
|
Definition
- It's contralateral, upside down and back to front
- Contralateral: ganglion cells laterally in the right eye receive information from L visual field, while ganglion cell neurons in the medial path of the contralateral eye (L eye) also receive input from lateral visual field therefore since these fibers sort out lateral and medial at the chiasm the Left Visual field of each eye is projected to the right cortex
- Upside down: the upper portions of visual field project below the calcarine fissure and lower parts to above the calcarine fissure
- Back to Front: medial to lateral can see fovea centralis on the posterior side and more peripheral regions of the eye as you move anterior |
|
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Term
|
Definition
| Loss in the visual fields of one or both eyes |
|
|
Term
|
Definition
|
|
Term
|
Definition
| You lose half of a visual field in one or both eyes |
|
|
Term
|
Definition
| You lose a quadrant i.e. quarter of your visual field in one or both eyes |
|
|
Term
| Differentiate Heteronymous and Homonymous visual loss |
|
Definition
| If both eyes affected and same visual field affected in both= Homonymous hemi or quadranthinopsia; different visual fields affected than heteromymous |
|
|
Term
| What visual loss would occur with a lesion in a section of the optic nerve |
|
Definition
| Blindness in affected eye |
|
|
Term
| What visual loss would occur with a lesion in a section of the optic tract |
|
Definition
| Right or left homonymous hemianopsia |
|
|
Term
| What visual loss would occur with a lesion in a section of crossing fibers in the chiasm |
|
Definition
|
|
Term
| What visual loss would occur with a lesion in a section of uncrossed fibers at chiasm |
|
Definition
|
|
Term
| Describe the Pupillary Light Reflex pathway (note: he did not cover this in lecture but it was in his additional notes) |
|
Definition
- The direct and consensual response
- Pathway: Retinal input to pretectal region, bilateral projection to nucleus of Edinger-Westphal, parasympathetic preganglionic fibers project to ciliary ganglia, postganglionics to constrictor pupillae muscles |
|
|
Term
| Describe the Tectal Pathways ((note: he did not cover this in lecture but it was in his additional notes)) |
|
Definition
a. Input to superior colliculus from retina, visual cortex, frontal eye fields, inferior colliculus, spinal cord
b. Tectospinal tract crossed, projects to lower motor neurons in upper cervical spinal cord
c. Tectobulbar tract crossed and uncrossed, projects to interneurons (interstitial nucleus of Cajal, nucleus of Darkschewitsch), which in turn project to motor nuclei of CN III, CN IV, CN VI
d. Coordination of head and eye movements utilizing visual input |
|
|
Term
| Lecture: Anatomy of the Cerebellum |
|
Definition
|
|
Term
| Describe the general function of the cerebellum |
|
Definition
| Integrates, coordinates and synchronizes motor activity of skeletal (striated) muscle. Influences activity of both upper motor neurons (UMN) and lower motor neurons (LMN) to achieve this control and acts at "subconscious" level |
|
|
Term
| The cerebellum somewhat forms the ___ of the 4th ventricle |
|
Definition
|
|
Term
| The cerebellum is composed of __ hemispheres and a central ___ |
|
Definition
| 2 hemispheres and a central vermis |
|
|
Term
| The surface of the cerebellum is folded into ridges called ___ and grooves called ___ |
|
Definition
Ridges= Folia
Grooves= Fissures |
|
|
Term
| What are the 3 lobes of the cerebellum and what are the two fissures that divide them |
|
Definition
1. Anterior lobe - In "front" of primary fissure, which separates it from next lobe
2. Posterior lobe - "Behind" primary fissure, extends around to postero-lateral fissure
3. Flocculo-nodular lobe - Smallest, and phylogenetically the oldest lobe; separated from posterior lobe by postero-lateral fissure |
|
|
Term
| Which is the only lobe that names the part of the vermis in that lobe |
|
Definition
| The Flocculo-Nodular names the Nodulus of the vermis (implied that the other two lobes include not only hemispheric regions but vermal regions as well, fissure go from side to side) |
|
|
Term
| What are the two regions of grey matter in the cerebellum |
|
Definition
1. Surface covered by cortex, comprised of three cell layers and is the same everywhere macroscopically and microscopically
2. Cerebellar nuclei, including the fastigial, globose, emboliform and dentate nuclei, buried in white matter underlying the cortex (sometimes called deep cerebellar nuclei but they are the only nuclei) |
|
|
Term
| The white matter in the Cerebellum is sometimes known as what? |
|
Definition
|
|
Term
| Describe the order of the four cerebellar nuclei from medial to lateral |
|
Definition
| The medial most is the Fastigal nucleus, lateral is the Globose and Emboliform nuclei and most laterally and largest of the fourth is the dendate nucleus so goes FGED |
|
|
Term
| The Globose and Emboliform nuclei are sometimes called what? |
|
Definition
| The interposed nuclei (interposed between fastigal and dendate) |
|
|
Term
| The dendate nucleus is sometimes called what? |
|
Definition
|
|
Term
| Describe the composition of the Inferior Cerebellar Peduncle |
|
Definition
Inferior cerebellar peduncle
- Associated with the Medulla
- Composed of larger restiform body and smaller juxtarestiform body
- Afferents from the vestibular nuclei, the spinal cord (via exclusively the dorsal spinocerebellar tract), from the lateral cuneate nucleus, from various trigeminal nuclei
- Efferents from cerebellum to vestibular nuclei |
|
|
Term
| Describe the composition of the Middle Cerebellar Peduncle |
|
Definition
Middle cerebellar peduncle
- Largest of the peduncles
- Consists only of afferents to cerebellum from pontine nuclei (note these fibers cross before entering the opposite peduncle); pontine nuclei relay info from cerebral cortex, motor cortex and other cortical material |
|
|
Term
| Describe the composition of the Superior Cerebellar Peduncle |
|
Definition
Superior cerebellar peduncle
- Largely efferents from cerebellar nuclei to a variety of motor regions
- With one exception, neurons from the cerebellar cortex do not leave the cerebellum they just leave the cortex; this exception is the projection back to the vestibular nuclei
- Small number of afferent tracts: ventral spinocerebellar (odd course, out to the stem, into cerebellum where it recrosses bringing information to the same side of the cerebellum as the dorsal spinocerebellar tract does) and mesencephalic nucleus of V carrying proprioception from the face; makes sence it's adjacent to superior cerebellar peduncle |
|
|
Term
| Functionally the Cerebellum can be divided into what 3 regions? |
|
Definition
1. Vestibulocerebellum
2. Spinocerebellum
3. Pontocerebellum
Note: cerebellar cortex looks the same everywhere so need to divide it based on source of inputs |
|
|
Term
| What Cortical Regions and Nuclei are associated with the Vestibulocerebellum |
|
Definition
Cortical regions – Flocculonodular lobe, uvula (portion of the vermis)
Nucleus – Fastigial nucleus |
|
|
Term
| What Cortical Regions and Nuclei are associated with the Spinocerebellum |
|
Definition
Cortical regions – Anterior lobe, portions of vermis and paravermal cortex of posterior lobe
Nuclei – Globose and emboliform nuclei |
|
|
Term
| What Cortical Regions and Nuclei are associated with the Pontocerebellum |
|
Definition
| Cortical regions – Lateral regions of cerebellar hemispheres Nucleus – Dentate nucleus |
|
|
Term
| What input does the Vestibulocerebellum region receive and what is it's function? |
|
Definition
- Reciprocally connected to vestibular nuclei ( only region of cortical grey matter that actually projects back out of the cerebellum)
-Regulates equilibrium and coordinates eye movements (makes sense, connection between vestibular nuclei via MLF to the CN nuclei of III, VI, and VI) |
|
|
Term
| What do Lesions in the Vestibulocerebellum cause |
|
Definition
- Produce swaying; unsteadiness; wide-based, unsteady gait
- No tremor; limb function generally intact
- Difficulties with eye movements (cerebellar nystagmus is seen) |
|
|
Term
| Describe a condition in which you can have a specific Vestibulocerebellum lesion |
|
Definition
| One condition in which you get a specific vestibulocerebellar problem; a tumour called medulla-blastoma grows up from floor of the 4th ventricle; occurs in infants and children, wont be detected in infants because they dont have locomotion yet, and there is no problem with tone or tremor but if you place them in center of crib, they can’t maintain upright posture, if they are supported along corner of a crib there isn’t a problem; equivalent of compensation in infants |
|
|
Term
| What input does the Spinocerebellum region receive and what is it's function? |
|
Definition
- Inputs from spinal cord and brainstem somatosensory nuclei (dorsal and ventral spinocerebellar tracts, lateral cuneate nucleus in medulla and from trigeminal sensory nuclei; these all bring in somato-sensory information)
- Regulates posture and gait |
|
|
Term
| What do Lesions in the Spinocerebellum cause |
|
Definition
- Produce cerebellar gait ataxia, an incoordination of leg movements; described as staggering or drunken gait
- Problems with tone and reflexes
- Rigidity and increased postural reflexes |
|
|
Term
| Lesions in Spinocerebellum can occur selectively due to what? |
|
Definition
| Malnutrition subsequent to chronic alcoholism |
|
|
Term
| What input does the Pontocerebellum region receive and what is it's function? |
|
Definition
- Input from pontine nuclei (relay from cortex)
- Involved in the planning and execution of learned, skilled, voluntary movements |
|
|
Term
| What do Lesions in the Pontocerebellum cause |
|
Definition
- Hypotonia and hyporeflexia
- Dysmetria - A tendency to undershoot or overshoot targets
- Intention tremor- at arms length
- Dysdiadochokinesis- difficultly executing rapidly alternating movements |
|
|
Term
| Name the 3 cell layers of the Cerebellar Cortex |
|
Definition
1. Molecular Layer
2. Purkinje Cell Layer
3. Granule Cell Layer |
|
|
Term
| Describe the Molecular Cell Layer |
|
Definition
- Includes stellate and basket cells, dendrites of Purkinje cells
- Stellate and basket cells are interneurons which form inhibitory synapses on Purkinje cell dendrites (stellate cells) or body (basket cells
- Not uniformly organized byt stellate more towards the surface and basket more towards the second layer |
|
|
Term
| Describe the Purkinje Cell Layer |
|
Definition
| Single layer of cell bodies of Purkinje cells (these send dendrites into the molecular layer) |
|
|
Term
| Describe the Granule Cell Layer |
|
Definition
- Includes granule and Golgi cells (more granule than Golgi)
- Axons of granule cells project to molecular layer, form excitatory synapses with either stellate or basket cells, or with dendrites of Purkinje cells
- Axons of Golgi cells in granule cell layer form inhibitory synapses upon elements in this layer |
|
|
Term
| Virtually all inputs to the cerebellar cortex terminate as what two fiber types? |
|
Definition
| Climbing fibers or mossy fibers |
|
|
Term
|
Definition
Climbing fibers originate from neurons in inferior olivary nucleus (olivary input is crossed and enters via the inferior cerebellar peduncle), ascend to molecular layer by 'climbing' through the 3 cell layers
- Form powerfully excitatory synapses with dendrites of Purkinje cells; essentially a one to one ratio between climbing fibers and purkinje cells so if a climbing fiber fires, so will the Purkinje cell |
|
|
Term
|
Definition
Mossy fibers represent all inputs to cerebellar cortex except those originating from inferior olivary nucleus (i.e. spinal input, cuneate input, pontine input, trigeminal input and vestibular input all ends up as morphologically distinguishable mossy fibers)
- Ascend to granule cell layer, form excitatory synapses with granule cells |
|
|
Term
| What happens after the synapses form on the granule cells |
|
Definition
- The axons of granule cells extend up into the molecular layer where they split T-wise and in one instance contact the distal portions of the Purkinje cell dendiritc tree forming excitory cell synapses out there but those excitory synapses given distribution and location are much less potent in terms of excitity Purkinje cells
- Granule cell axons may also contact Stellate or Basket cells; these two cell types form synapses in the case of the Stellate cells with Purkinje cell dendrites and for basket cells with Purkinje cell bodies; basket cells make a plexus of synaptic complexes around Prukinje cell bodies (why it’s called basket cells)
- Those two neuronal types: stellate and basket cells are inhibitory so by activating mossy fibers you can have mildy excitory affect or through cortical interneurons an inhibitory affect on Purkinje cells |
|
|
Term
| Sole output from the cerebellar cortex occurs via what cell type? |
|
Definition
| Via axons of Purkinje Cells. All cerebellar cortical circuitry designed to regulate firing of Purkinje cells |
|
|
Term
| Purkinje cells project mainly to what? |
|
Definition
Mainly but not exclusively to cerebellar nuclei
Note: Very few, those of the vestibulocerebellum will go back to vestibular nuclei (exception to the general rule) |
|
|
Term
| Purkinje axons form what type of synapse on neurons in cerebellar nuclei |
|
Definition
| Inhibitory (uses GABA to turn off cerebellar nuclei) |
|
|
Term
| If output from the cerebellum originates chiefly from cerebellar nuclei mediated by Purkinje fibers and they form inhibitory synapses only, how is cerebellar output modulated? |
|
Definition
- To modulate firing of neurons in cerebellar nuclei, there must also be excitatory input to these nuclei
- Excitatory input to cerebellar nuclei provided by collaterals of axons that project to cerebellar cortex
- Spinal cord, vestibular nuclei, reticular formation, inferior olivary nucleus all contain neurons whose axons form excitatory synapses on neurons in cerebellar nuclei |
|
|
Term
| Describe the Cerebellar Circuitry of the Vestibulocerebellum i.e. Inputs, and Outputs down to the level of LMN and or UMN |
|
Definition
INPUT: derived from vestibular ganglia directly and from vestibular nuclei (same kind of info), and from inferior olivary nucleus
INPUT VIA: Inferior Cerebellar Peduncle, Excitatory to cortex (Floculonodular lobe+uvula) and via collaterals excitatory to Fastigal Nucleus
VESTIBULOCEREBELLAR CORTICAL OUTPUT: directed to vestibular nuclei (through ICP; inhibitory) and to Fastigal Nuclei (Through Purkinje Fibers; Inhibitory)
FASTIGAL NUCLEI OUTPUT: directed to vestibular nuclei also (through ICP; excitatory) and to Thalamus (through SCP; excitatory)
VESTIBULAR NUCLEI OUTPUT: to LMN in the stem and cord via the MLF to motor nuclei of III, IV, VI and lateral vestibulospinal tracts to LMNs in the spinal cord
THALAMIC OUTPUT: to upper motor neurons in the cerebral cortex (typical for thalamus) |
|
|
Term
| The vestibulocerebellum therefore influences which: lower or upper motor neurons |
|
Definition
|
|
Term
| Describe the Cerebellar Circuitry of the Spinocerebellum i.e. Inputs, and Outputs down to the level of LMN and or UMN |
|
Definition
INPUT:from spinal cord and brainstem (spinocerebellar and cuneocerebellar projections, trigeminal nuclei) and inferior olivary nucleus
INPUT VIA: ICP and some via SCP excitatory to both the cortex (vermal and paravermal regions) and excitatory collaterals to the nuclei (globose and emboliform)
SPINOCEREBELLUM CORTICAL OUTPUT: Some inhibitory to the Fastigal Nucleus (of the Vestibulocerebellum) and inhibitory to Nuclei (Globose and Emboliform) via Purkinje fibers
GLOBOSE AND EMBOLIFORM OUTPUT: Excitatory output to the Thalamus and the Red Nucleus: magnocellular and Reticular Formation all through the SCP
THALAMUS OUTPUT: to UMN in Cerebral Cortex
RED NUCLEUS: MAGNOCELLULAR OUTPUT: LMN in stem and cord via the Rubrospinal tracts (locomotion)
RETICULAR FORMATION: LMN in stem and cord via Reticulobulbar and Reticulospinal tracts respectively (locomotion) |
|
|
Term
| Describe the Cerebellar Circuitry of the Pontocerebellum i.e. Inputs, and Outputs down to the level of LMN and or UMN |
|
Definition
INPUT: Pontine Nuclei and Inferior Olive
INPUT VIA: MCP for the Pontine Nuclei and ICP for Inferior Olive both form excitatory synapses with both the Cortex (lateral hemispheres) and the Dendate Nucleus
PONTOCEREBELLAR CORTICAL OUTPUT: Inhibitory on the Dendate Nucleus via Purkinje fibers
DENDATE NUCLEUS OUTPUT: Directed at the Red Nucleus: Parvocellular and the Thalamus, both excitatory and through the SCP
RED NUCLEUS: PARVOCELLULAR OUTPUT: Inferior Olive (cerebellum kept aware of own activity)
THALAMUS OUTPUT: UMN in cerebral cortex |
|
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Term
| Draw out the Cerebellar Circuitry for the Vestibulocerebellum, the Spinocerebellum and the Pontocerebellum |
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Definition
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Term
| T or F: All 3 cerebellar portions receive input from the Inferior Olive |
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Definition
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Term
| How do the 3 functional regions reflect a hierarchy of complexity of movement |
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Definition
Simply orienting yourself to gravity (vestibulocerebellum= equillibrium), to moving through space (spinocerebellum) to manipulating objects in that space (Pontocerebellum)
Note: this is also reflected in size i.e. dendate and pontocerebellar cortex are the largest |
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Term
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Definition
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Term
| Define the Basal Ganglia (previously thought definition and current) |
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Definition
| Originally, the term “basal ganglia” referred to a group of large gray masses (nuclei) found at the base of the cerebral hemispheres. Current usage include these and diencephalic and mesencephalic structures to which they are connected that together form a circuit for controlling certain kinds of motor activity. Odd terminology because they are all nuclei, not ganglia and only 2/4 are basal. |
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Term
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Definition
1. Lentiform Nucleus
2. Caudate Nucleus
3. Subthalamus
4. Substantia Nigra |
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Term
| Describe the Lentiform Nucleus Anatomically |
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Definition
- Found lateral to the internal capsule and deep to the insula
- Biconvex with greater convex on medial aspect
- Consists of two subnuclei the Putamen and the Globus Pallidus
- the Putamen is the outermost portion
- Globus Pallidus in the innermost and contains two regions, the Globus Pallidus externa (region closest to the putamen) and the Globus Pallidus interna (region medial to the externa) |
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Term
| Describe the Caudate Nucleus Anatomically |
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Definition
- Caudate nucleus consists of a head region, which bulges into the lateral ventricle, and a long, tapering tail region which curves to extend down into the temporal lobe and end adjacent to the amygdala, to which it is nevertheless not related
- Caudal is in front and medial to the anterior limb of the internal capsule |
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Term
| What term is given to the 'Classically defined Basal Ganglia' |
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Definition
| The region occupied by the basal ganglia at the base of the forebrain i.e. the classically defined basal ganglia (Lentiform and Caudate) is THE CORPUS STRIATUM |
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Term
| How is the Corpus Striatum divided functionally? |
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Definition
1. Neostriatum (or simply striatum; 'newer
part of corpus striatum): the putamen and caudate nucleus
2. Paleostriatum (or simply pallidum): The globus pallidus
Note: Despite being subdivisions of the Lentiform the Putamen and Globus Pallidus are not functionally related. It's the Caudate and Putamen that are continuous and represent essentially subdivisions of the same nucleus |
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Term
| Describe the physical connection between the caudate and putamen |
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Definition
| Caudate and putamen are continuous with one another around the anterior limb of the internal capsule. The region of communication is called the nucleus accumbens |
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Term
| The Subthalamus is the ____ motor nucleus and the Substantia Nigra is the ____ motor nucleus |
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Definition
Subthalamus= Diencephalic Motor Nucleus
Substantia Nigra= Mesencephalic Motor Nucleus |
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Term
| Name the Two Portions of the Substantia Nigra |
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Definition
| The Compact Part (pars compacta) and the Reticular Part (pars reticulata) |
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Term
| How do the Pars Compacta and Pars Reticulata of the Substantia Nigra differ in appearance |
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Definition
| The compact region stains darker due to melanin in the cell bodies of the neurons located here which is a biproduct of the transmitter used here=dopamine, the reticular region is not pigmented as it uses GABA |
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Term
| What is the function of the basal ganglia? |
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Definition
| Output from the basal ganglia influences the activity of "upper motor neurons" in the motor cortex. There are no direct descending projections from the basal ganglia to "lower motor neurons" in the stem or cord (unlike cerebellum that affects both UMN and LMN) |
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Term
| Motor influences of the basal ganglia are mediated via what two pathways? |
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Definition
| The Direct and Indirect Pathway |
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Term
| Describe the two major differences between the direct and indirect pathways |
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Definition
The direct pathway: Does not involve the subthalamus; activation has the effect of increasing cortical motor output
The indirect pathway: Involves the subthalamus; activation has the effect of decreasing cortical motor output |
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Term
| List the steps in the Direct Pathway |
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Definition
Motor cortex ─− (excitatory) → to striatum −− (inhibitory) → to globus pallidus interna −− − (inhibitory) → to thalamus −− (excitatory) → to motor cortex
Note: thalamus also projects back to the Striatum (closing the loop) |
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Term
| List the Steps in the Indirect Pathway |
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Definition
Motor cortex −− (excitatory) → to striatum −− (inhibitory) → to globus pallidus externa −−− (inhibitory) → to subthalamus −− (excitatory) → to globus pallidus interna −− (inhibitory) −
→ to thalamus −− (excitatory) → to motor cortex
Note: thalamus also projects back to the Striatum (closing the loop) |
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Term
| The Basal Ganglia Pathway involves what thalamic nuclei? |
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Definition
| Ventral Anterior Mototr Nucleus |
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Term
| What is the result of these two pathways (direct and indirect) operating? |
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Definition
| These two pathways operate in conjunction, essentially modulating the excitatory thalamic projection to premotor cortex, thus influencing motor output from primary motor cortex |
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Term
| The Substantia Nigra is reciprocally connected to what structure? |
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Definition
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Term
| What is the function of the Substantia Nigra in the Basal Ganglia Motor Pathway? |
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Definition
| Activating the substantia nigra excites the direct pathway and inhibits the indirect pathway thus having a synergistic effect on motor cortical output. done through dopamine projections, the way we think this works is neurons from the Striatum in the direct pathway are D1 dopamine receptors which are excitatory and in the indirect pathway are D2 dopamine receptors which are inhbiitory and close down that pathway. |
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Term
| Draw out the Motor Pathway for the Basal Ganglia |
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Definition
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Term
| Movement disorders resulting form lesions affecting the basal ganglia are called what? |
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Definition
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Term
| Name 3 Examples of Diseases that involve the Basal Ganglia |
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Definition
1. Parkinson's Disease
2. Huntington's Chorea
3. Hemiballismus |
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Term
| Describe Parkinsons: basic pathophysiology and the symptoms |
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Definition
- Results in degeneration of the dopaminergic neurons in the pars compacta of the substantia nigra
- Classified as a hypokinetic disease
- Get Rigidity known as cogwheel rigidity
- Mask-like facial expression, little spontaneous movements of face or facial expression
- Stiff gait, shuffling and leaning forward= called a festinating gait
- Resting tremor (sometimes called pill rolling), that diminishes with movement |
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Term
| Describe Huntington's: basic pathophysiology and the symptoms |
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Definition
- Autosomal Dominate genetic disease with anatomical changes observed in the striatum (caudate and putamen) and frontal lobes
- Thought to be due to exctio-toxcity at NMDA receptors
- Classified as a hyper kinetic disease
- Choreiform movements (repetitive and rapid, jerky, involuntary movement)
- Eventual dementia |
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Term
| Describe Hemiballismus: basic pathophysiology and the symptoms |
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Definition
- Results from lesions, often vascular, in the subthalamus
- Classified as a hyperkinetic disease
- Violent, uncontrollable contractions of proximal limb musculature on the side of the body contralateral to the site of the lesion
- Note: lesion specific to subthalamus most likely vascular usually an infarct involving postero-medial ganglionic or penetrating arteries arising from the proximal portion of the posterior cerebral artery |
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Term
| Movement disorders resulting form basal ganglia lesions are grouped under the heading of '_____' syndromes |
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Definition
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Term
| Why is the term extrapyramidal syndromes not accurate? |
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Definition
- Designation arose from the early assumption that the basal ganglia were the source of direct descending projections to lower motor neurons outside the pyramidal tract since the deficits differed from those affecting the cerebellum or motor cortex (i.e. UMN)
- Now know that this is not the case, as the basal ganglia primarily affect the functioning of upper motor neurons, not lower motor neurons
- However Clinically a useful designation, as it is understood to apply to certain kinds of movement deficits |
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Term
| Which motor structure projections to LMN actually run outside the pyramidal tracts? Are lesions in these considered extrapyramidal syndromes. |
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Definition
| Such structures as the tectum, reticular formation, red nucleus, and vestibular nuclei do give rise to projection to LMN outside the pyramidal tracts (tectospinal, tectobulbar, rubrospinal, vestibulospinal), but these are not involved directly in what are clinically defined as extrapyramidal syndromes |
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Term
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Definition
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Term
| Name the 4 Components of the Diencephalon |
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Definition
| Thalamus, Hypothalamus, Subthalamus, Epithalamus |
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Term
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Definition
- A large collection of nuclei bordering the third ventricle
- Generally speaking, nuclei receive input from subcortical sources (both motor and sensory and some memory) and are individually reciprocally connected with the cerebral cortex
- May be considered the "gateway to the cortex"; processes incoming info and passes it to the cortex |
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Term
| Both the thalamus and the hypothalamus are lateral to what? |
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Definition
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Term
| The thalamus is anatomically divided into __ number of major nuclear groups by the ___- |
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Definition
| 4 nuclear groups by the internal medullary lamina |
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Term
| Name the 4 Major Nuclear Groups of the Thalamus |
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Definition
1. Anterior nucleus (can be subdivided but we consider it as one)
2. Medial nucleus (largely the dorsomedial nuclear group)
3. Lateral nuclear group
4. Intralaminar nuclei (found within internal medullary lamina) |
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Term
| What are the components of the Lateral Nuclear Group and how are they divided? |
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Definition
Lateral nuclear group: Consists of a dorsal tier and a ventral tier of nuclei
Dorsal tier: Lateral dorsal and lateral posterior nuclei; pulvinar
Ventral tier: Ventral anterior, ventral lateral. ventral posterior (with lateral and medial divisions), lateral geniculate body, medial geniculate body |
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Term
| Name the 3 Functional Groups of Nuclei found in the Thalamus |
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Definition
1. Relay Nuclei
2. Association Nuclei
3. Non-specific Nuclei |
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Term
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Definition
| Relay nuclei: Receive input from limited, defined regions of the central nervous system; project to restricted areas of cortex; mediate specific functional modalities, be they sensory, motor, or limbic |
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Term
| Define Association Nuclei |
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Definition
| Association nuclei: Receive input from a variety of sources, including other thalamic nuclei; project to number of cortical areas; involved in integration and correlation (“association”) of a variety of modalities |
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Term
| Define Non-Specific Nuclei |
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Definition
| Non-specific nuclei: Receive input from the brainstem reticular formation, output directed at widespread regions of the cortex, involved in cortical activation |
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Term
| ANTERIOR NUCLEUS: type, input, output, function |
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Definition
TYPE: Relay
INPUT: Hippocampal Formation and Mamillary Bodies (Hypothalamus)
OUTPUT: Cingulate gyrus
FUNCTION:Thalamic Nuclei in the Limbic System; Emotional states related to basic drives, memory |
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Term
| MEDIAL NUCLEUS: type, input, output, function |
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Definition
TYPE: Association
INPUT: Receives input from hypothalamus, amygdala, other thalamic nuclei
OUTPUT: Connects reciprocally to widespread regions of the frontal lobe especially prefrontal cortex
FUNCTION: Involved in moods, affect, certain emotional states |
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Term
| All of the Lateral Nuclear Group are what type of nuclei? |
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Definition
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Term
| VENTRAL ANTERIOR NUCLEUS: type, input, output, function |
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Definition
TYPE: relay
INPUT: Substantia nigra and Globus pallidus
OUTPUT: Premotor and supplementary motor cortices
FUNCTION: Mediates basal ganglia control of upper motor neurons |
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Term
| The Ventral Anterior Nucleus by influencing the Basal Ganglia is responsible for allowing you to perform voluntary movements |
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Definition
| Not entirely, it's what lets you initiate and control these voluntary movements but its the primary motor cortex and its projections that lets you perform the functions themselves |
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Term
| VENTRAL LATERAL NUCLEUS: type, input, output, function |
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Definition
TYPE: relay
INPUT: Mainly Dentate nucleus of cerebellum, lesser amounts from substantia nigra and globus pallidus
OUTPUT: Primary motor cortex (Frontal Lobe)
FUNCTION: Mediates esp. cerebellar influences for control of fine, learned movements |
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Term
| The Ventral Anterior (assoc with basal ganglia) and Ventral Lateral (assoc with cerebellum) both project to ___ structures and are engaged in motor influences onto ___ regions ultimately |
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Definition
| Project to Frontal Lobe Structures and engaged in referring motor influences on UMN regions ultimately |
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Term
| Ventral Posterior Nucleus consists of what two subnuclei |
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Definition
| Ventral Posteriolateral (VPL) and Ventral Posteromedial (VPM) |
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Term
| VENTRAL POSTERIOR NUCLEUS (VPL AND VPM): type, input, output, function |
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Definition
TYPE: Relay
INPUT: Somatosensory Pathways (medial lemniscal and spinothalamic to VPL, and trigeminothalamic to VPM)
OUTPUT: Primary sensory cortex
FUNCTION: Somatosensation (pain, temperature, touch, pressure and proprioception) for head and body |
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Term
| LATERAL GENICULATE BODY: type, input, output, function |
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Definition
TYPE: Relay
INPUT: Retina via optic tract
OUTPUT: Primary visual cortex in occipital lobe
FUNCTION: Associated with visual pathway |
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Term
| How is the Lateral Geniculate Body Organized? |
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Definition
| It's a layered nucleus with crossed fibers going to layers 1,4,6 and uncrossed to 2,3,5 |
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Term
| MEDIAL GENICULATE BODY: type, input, output, function |
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Definition
TYPE: Relay
INPUT: From Auditory pathway via the inferior colliculus (which gets it from Lateral Leminiscus)
OUTPUT: Primary auditory cortex in temporal lobe (bilaterally)
FUNCTION: Associated with pathway for hearing |
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Term
| Why are lesions invading the primary auditory lesion on the Left more severe than the right? |
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Definition
| Left side primary auditory cortex is related inevitably with speech (for most people) and therefore left sided lesions invading the auditory area tend to be more serious than R sides lesions |
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Term
| LATERAL DORSAL NUCLEUS: type, input, output, function |
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Definition
TYPE: Relay
INPUT: Hippocampus
OUTPUT: Cingulate gyrus
FUNCTION: Like anterior nucleus, associated with limbic system (lies just behind anterior nucleus) |
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Term
| The Lateral Posterior Nucleus is often associated with what other nuclei in the thalamus? |
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Definition
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Term
| LATERAL POSTERIOR NUCLEUS AND PULVINAR: type, input, output, function |
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Definition
TYPE: Both Associatation
INPUT: Lateral Posterior= Reciprocally with Parietal cortex, Pulvinar= Recriprocally with cortex of parietal, occipital, and temporal lobes; some visual input
OUTPUT: Lateral Posterior= association somatosensory cortex of Parietal; Pulvinar= association sensory cortex of pariental, occipital and temporal lobes
FUNCTION: Both nuclei are involved in integrating sensory functions, including those related to hearing, sight, and somatosensation, and “making sense" of incoming sensory information |
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Term
| T or F: The lateral posterior nucleus and pulvinar are examples of primary sensory areas |
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Definition
| False, not places where raw data is positioned, these are places that associate various kinds of sensory information so you can make sense of what you’re receiving and correlate various sensations |
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Term
| The Intralaminar Nuclear Group is defined as what? |
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Definition
| Group includes a variety of nuclei (e.g. intralaminar, centromedian) which are found embedded in the internal medullary lamina of the thalamus |
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Term
| INTRALAMINAR NUCLEAR GROUP: type, input, output, function |
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Definition
TYPE: non-specific
INPUT: Brainstem reticular formation
OUTPUT: Widespread regions of cerebral cortex
FUNCTION: Cortical activation, arousal |
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Term
| Define Thalamic Syndrome i.e. what causes it and what are the symptoms |
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Definition
- Caused by ischemia or hemorrhagic stroke affecting VPL and VPM
- Posteromedial penetrating arteries arising from proximal posterior cerebral may be involved
- Symptoms seen contralateral to site of lesion
- Severe impairment of position sense, with possible sensory ataxia (inability to appropriately coordinate locomotory movements not because of cerebellar issues but because sensory information disrupted)
- Initially don't see affect on pain and temperature probably due to alternative pathways but with partial recovery, may see increased pain sensitivity which is resistant to drug treatment= thalamic pain
- Get Hyerpathia= noxious stimulus to skin produces disagreeable pain |
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Term
| Define the Function of the Hypothalamus |
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Definition
Consists of a collection of nuclei involved with regulation of visceral function and the maintenance of homeostasis, mediation of limbic function (memory)
- Visceral activity includes regulation of smooth muscles in vessels and gut, visceral response to emotional states
- Homeostasis includes regulation of temperature, osmotic gradients, food and water intake |
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Term
| What two ways does the hypothalamus employ it's affects |
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Definition
- Nuclei are connected via conventional neural pathways
- Acts as a neuroendocrine organ i.e. functions via the manufacturing and release of hormones
- Employs neural pathways conveying information to and from hypothalamic nuclei that affect particularly autonomic activity, and neuroendocrine modulation based on information derived from composition of blood circulating through hypothalamus |
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Term
| The Hypothalamus consists of what groups of nuclei? |
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Definition
The Lateral Group: consists of sparse cells forming ill-defined nuclei located lateral to columns of fornix
The Medial Group: better organized, consists of a number of discrete nuclei |
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Term
| The Medial Group of Nuclei are named somewhat based on what? |
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Definition
| Relation to the Optic Chiasm |
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Term
| Name the Medial Group of Nuclei according to their relation to the optic chiasm |
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Definition
In front of optic chiasma: preoptic area
Above optic chiasma: supraoptic, anterior, paraventricular
Above infundibular stem: Infundibular, ventromedial, dorsomedial
Behind infundibular stem: mamillary bodies, posterior |
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Term
| What is the Function of the Lateral Group of Nuclei |
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Definition
| Involved in regulation of feeding behaviour |
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Term
| What does stimulation vs. destruction of the Lateral Group of Nuclei cause |
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Definition
| Stimulation of lateral group results in the initiation of eating behavior, while destruction of nuclei in this region produces aphagia= cessation of eating |
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Term
| What Nuclei is the opposite of the Lateral Group of Nuclei? |
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Definition
| Ventromedial Nucleus; Satiety center, stimualtion of these cells induce cessation of eating and lesions here produce excess eating or hyperphagia |
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Term
| How do the Lateral Group of Nuclei vs. the Ventromedial Nucleus operate in terms of which of the two hypothalamic mechanisms they employ? |
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Definition
| They both work via conventional neuro pathways |
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Term
| Name two medial nucleus that employs both neural and endocrine control |
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Definition
| Paraventricular Nucleus and Supraoptic |
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