Term
| The nerve cell body is known as 2 other names... |
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Definition
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Term
| What does the cell body of a neuron contain? (8) |
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Definition
1. nucleus with euchromatin (uncoiled chromosomes)
2. large nucleoli for active transcription
3. nissl substance
4. RER but not at the axon hillock
5. extensive Golgi
6. mitochondria
7. neurofilaments - agrophilic intermediate filaments
8. lipofuscin |
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Term
| what do the dendrites of a neuron contain? (2) |
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Definition
microtubules and neurofilaments for transport
- sparse ribosomes |
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Term
| what do axons of neurons contain? (3) |
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Definition
- microtubules and neurofilaments for transport
- plasma membrane of the axon - axolemma, cytoplasm and axoplasm
- axon sheath from oligodendrocytes in the CNS and schwann cells in the peripheral nervous system - may be myelinated or not and branch at their terminal before synapsing |
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oligodendrocyte
- what disease is associated? |
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Definition
| glial cell producing myelin sheaths for axons in the CNS and can myelinate many neurons; injured in multiple sclerosis (autoimmune disease attacking myelin) |
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Term
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Definition
produce myelin sheaths for neurons in the PNS or envelope axons that are nonmyelinated
- can myelinate one neuron or envelope several axons |
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Term
anterograde flow
- requires what?
- what progresses at a slow speed
- fast speed |
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Definition
macromolecules are transported from the cell body to axon terminal
- requires ATP dependent, microtubule dependent kinesin
- slow speed = 1 mm/day = proteins and microfilaments
- fast speed = 100 mm/day = organelles, vesciles for neurotransmission |
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Term
retrograde flow
- which molecule is used |
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Definition
fast flow towards the cell body with products of endocytosis such as toxins, viruses, tetanus; dyes are used for tracing
- dynein is ATp dependent and microtubule dependent |
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Definition
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Definition
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Definition
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Term
| what is the pattern of impulse flow? |
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Definition
1. dendrites to
2. soma to
3. axon to
4. axon terminal |
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Term
| what is the presynaptic component of synapses? |
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Definition
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Term
| what are three types of postsynaptic components of synapses? |
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Definition
1. soma - axosomatic
2. dendrites - axodendritic
3. axons - axoaxonic |
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Term
| what does depolarizing do? hyperpolarizing? |
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Definition
depolarization = excitatory
hyperpolarization = inhibitory |
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Term
| synaptic vesicles contain _____ and cause ______ to open and close or initiate _____ |
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Definition
neurotransmitters
- ion channels
- second messenger cascades |
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Term
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Definition
at the neuromuscular junction
- neurons secreting this are called cholinergic |
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Term
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Definition
- neurons that secrete norepinephrine are noradrenergic
- examples - norepinephrine, epinephrine, dopamine
- aka biogenic amine
-packaged in large, spherical dense core vesicles |
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Definition
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Definition
neurotransmitter
- excitatory
neurons using it are glutametergic
- packaged in small, clear, spherical vesicles
- postxynaptic membrane is electron dense |
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Definition
inhibitory neurotransmitter
- gabaergic
- packaged in elongated clear vesciles |
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Term
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Definition
5-hydroxytryptamine (5-HT) neurotransmitter; also known as a biogenic amine
- packaged as large, spherical, dense core vesicles |
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Term
| what are neuromodulators? examples |
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Definition
- modify sensitivity of neurons to neurotransmitters
- neuropeptides like B-endorphin and steroids in nerve tissue and steroids in systemic circulation |
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Term
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Definition
do not propagate action potentials but maintain a favorable environment for neurons
examples;
- oligodendrocytes
- astrocytes
- microglia
- ependymal cells
- schwann cells
- satellite cells |
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Term
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Definition
1. fibrous - few long processes in white matter (axon rich)
2. protoplasmic - may short, branched processes in gray matter (cell body rich)
- end processes form continual layer around capilaries |
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Term
| what are astrocyte functions? 3 |
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Definition
1. control composition of extracellular fluid] around neurons
2. transport of moleculees from blood to neurons
3. release metabolic and neuroactive molecules such as enkephalins |
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Term
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Definition
agressive phagocytic cells
- release proteases and oxidative free radicals
- dispose cell debris |
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Term
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Definition
neuroepithelial cells that do not form neurons but line brain ventricles and central canal of spinal cord
- cilia move CSF
- junctions provide barrier between CSF and nerve tissue |
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Definition
glial cell
- associated with cell bodies in the ganglia
- non-myelinating |
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Definition
| connective tissue membranes coveing the central nervous system such as the brain and spinal cord |
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Definition
| dense connective tissue continuous with the periosteum of skull of vertebrae |
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Definition
| potential space betwen dura and arachnoid |
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Definition
cob-web like structure with 2 layers
- 1 layer in contact with the dura
- 1 layer of trabeculae connecting the pia |
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Term
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Definition
| space between trabeculae as a reservoir for CSF |
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Term
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Definition
| loose CT with blood vessels covering the brain and spinal cord |
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Term
blood brain barrier
- how it worksq |
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Definition
reduced permeability of endothelial cells in blood capillaries of nervous tissue
- reduced fenestratinons in the endothelial cells
- tight junctions between cells
- few pinocytotic vesicles |
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Term
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Definition
| made of invaginated folds of pia mater, rich in blood, creates CSF |
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Term
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Definition
fills brain ventricles and spinal cord central canal
- impt for CNS metabolism and protects from mechanical shock |
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Definition
| axon + coverings (schwann cells or oligodendroyctes) - make up tracts in brain, spincal cord and peripheral nerves |
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Term
1. large/short axons conduct faster
2. myelinizationn ___ velocity
3. nodes of ranvier have many ___ channels
4. afferent =
5. efferent = |
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Definition
1. larger
2. increases
3. Na+
4. info flows towards teh CNS (sensory)
5. info flows away from CNS - motor |
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Term
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Definition
| impluse leaps from node to node and is 50x faster in myelinated nerves |
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Term
| what does gray matter contain?> |
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Definition
| neuronal cell bodies and processes |
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Term
| what does white matter contain? |
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Definition
| myelinated axons and oligodendrocytes - NO cell bodies |
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Term
| how many layers makes up the cerebral cortex? which layers have cells? what is deep to the cerebal cortex? what is a nuclei in the brain? |
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Definition
6 layers
- superficial layer is acellular; 5 other layers have cells
- deep to the cortex is white matter and nuclei
- nuclei are clusters of neuronal cell bodies with shared functions and of similar type (ex. caudate nucleus, olivary nucleus) |
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Term
| what layers make up the cerebellum? |
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Definition
1. molecular layer
2. Purkinje cell layer
3. granular layer |
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Term
| in the spinal cord, which is deep (white/gray matter) |
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Definition
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Term
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Definition
| group of nerve cell bodies related in function |
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Term
in the cortex, columns are oriented.... to the plane of the cortex.
in the spinal cord, columns are oriented ---- to the length of the spingal cord |
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Definition
cortex- perpendicular
spinal cord - extends length (ex. clarke's column) |
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Term
| what is a layer, lamina, or strata? how are they oriented? |
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Definition
| group of functionally related cells that form a layer oriented parallel to the plane of the larger neural structure (layer VI of cerebral cortex) |
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Term
| what is a tract, fasciculus, or lemniscus? |
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Definition
| bundle of parallel axons in the CNS |
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Term
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Definition
| group of several parallel tracts or fasciculi |
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Term
| what is a nerve, root, or ramus? |
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Definition
| peripheral structure consisting of parallel axons and associated cells |
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Term
endoneurium
- matrixx is secreted by ____
- includes type ___ collagen fibrils and occassional _____ |
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Definition
- schwann cells
- III
- fibroblasts |
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Term
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Definition
| sheath of flattened fibroblast surrounding fascicles |
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Term
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Definition
| dense CT surrounding an entire nerve, includes fibroblasts and type I collagen |
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Definition
| group of nerve cell bodies located in a peripheral nerve or root; forms a visible knot |
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Term
| autonomic ganglia - contain cell bodies of the ____ganglionic neurons for synapsing. _____ cells are also present here |
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Definition
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Term
| sypmathetic ganglia - the pre-ganglionic neuron is _____ and the post-ganglionic neuron is ____ |
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Definition
- cholinergic
- noradrenergic |
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Term
| parasympathetic ganglia - pre and post ganglionic neurons are _____ |
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Definition
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Term
| sensory ganglia contain _________ and _____ cells and have no synapses |
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Definition
- sensory neuron cell bodies
- satellite cells |
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Term
| What contributes the most to the blood brain barrier? |
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Definition
| nonfenestrated endothelial cells (see other questions for other answers) |
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Term
| which type of glial cell derives from bone marrow? |
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Definition
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Term
which statement is false?
1. sympathetic neurons are efferent
2. postganglionic cells in the parasympathetic system are cholinergic
3. lipofuscin refers to vesicles containing pigmented particles that are undegraded products from lysosomes
4. sensory neurons synapse in the dorsal root ganglion
5. the molecular layer of the cerebellym is mostly filled with large dendritic arbors of purkinje cells, which accounts for the small number of nuecli here. |
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Definition
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Term
| which type of glial cell is associated with grey matter? |
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Definition
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Term
| When will axons regnerate in the PNS? |
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Definition
after a crushing injury and sometimes after being severed - portion distal to the injury degrades and regrows from the proximal portion of the axon
- schwann cells lose myelin but cell bodies remain and gyide regrowth of the axon |
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Term
| When will axons regenerate in the CNS? |
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Definition
| little or no regeneration occurs |
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