-Brain (cerebrun, brainstem, cerebellum)

-Spinal cord

-dura mater

-BBB

-Autonomic NS

-Somatosensory NS

-Somatic NS

-parasympathetic

-sympathetic

-enteric

-carries sensory information to the CNS

-sensoryis afferent

-voluntary movement

-motor is efferent

-Spinal nn: pairs branch into small nn and innervate the limbs, trunk, and caudal region

-Cranial nn: pairs innervate the head and neck

-carry info from the body to the spinal cord or brain stem=> then to the cerebellum and cerebrum for interpretation OR form a reflex arc in the spinal cord

-Function: body position and balance, touch, pain, temp, and the special senses of taste, hearing, vision, and smell

-carry responses to the sensory signals from the spinal cord and brain back to the body

-Function: regulate voluntary movements and muscle control

-monosynaptic

-muscle

-ACh

-ventral grey horn

-ventral

-TL

-PL

I. Olfactory (S)

II. Optic (S)

III. Oculomotor (M)

IV. Trochlear (M)

V. Trigeminal (B)

VI. Abducens (M)

VII. Facial (B)

VIII. Vestibulocochlear (S)

IX. Glossopharyngeal (B)

X. Vagus (B)

XI. Accessory (M) 

XII. Hypoglossal (M)

-cranial nn

-reticular activating system, gait, respiratory center

-General somatic efferent: innervate voluntary skeletal m

-General visceral efferent: innervate involuntary smooth m of the blood vessels and visceral organs, the glands, and cardiac m of the heart

-LMN: from spinal cord to muscle

-UMN: from brain to spinal cord

-Patellar= femoral n

-Flexor or withdrawal= sciatic n

-broad response most of brachial plexus and many n branches

-Hypo or areflexia: loss of reflex

-Weakness

-Hypotonia or atonia: loss of motor tone

-Neurogenic atrophy

1) Initiate volunatry motor activity: gait generation

2) Maintain m tone to counter gravity and to establish posture

3) control visceral function

1) Abnormal gait

2) Spasticity: interruption of extensor and flexor activation

3) Paresis (weakness)

4) Hyperreflexia due to loss of inh input

5) Loss of conscious proprioception: ataxia

-YES

-called Decussate

-if in right, see abnormality on right side

-if in brain would see paralysis on opposite side

-spinal

-peripheral

-cranial

-excitable

-Na/K pump

-number of APs

-conveyed by the properties of the receptor and the CNS target that are activated

Definition: Adaptation

-Is it rapid or slow?

-diminishing of depolarization despite sustained stimulus

-rapid or slow adapting receptors

-Somatosensory: mechanical, thermal, proprioception (body in space), nociception (pain)

-vision

-auditory

-olfactory

-gustatory (taste)

-vestibular

-thermal: thermoceptors: free nerve endings

-pain: nociceptors: free nerve endings

-Meissner's corpuscle: rapidly adapting

-Pacini's corpuscle: foot pads, rapidly adapting

-Ruggini's corpuscle: slowly adapting

-Merkel's disks: slowly adapting

Describe mechanoreceptors

-structure?

-response to stimulus?

-adaptation rate?

-Structure: shaped like an onion-like capsule around fluid center with a free nerve ending of afferent sensory neurons

-Response to stimulus: when compressed, the mem transforms and the channels open=> return to original structure once P is released

-Rapid adaptation due to the slipping of the layers

-afferent sensory neurons and travel in peripheral nerves

-cell bodies in dorsal root ganglia at each segmental spinal nerve

-dorsal root ganglia=> dorsal root=> dorsal spinal cord=> medulla

-nucleus gracilis

-cuneate cuvleus

-cross

-from medulla to the thalamus

-decussate at the medulla [in the internal arcuate tract] and projects to the thalamus

-from thalamus to sensory cortex where topographic maps of the body exist

-part of the cerebral cortex that integrates mechanosensory input= parietal lobe

Definition: Proprioception

-what are its receptors called?

-the awareness of where ones body is

-proprioceptors: give info on position of limbs and other body regions

-msucle spindles

-golgi tendon organs

-joint receptors

-msucle spindles

-golgi tendon organs

-intrafusal

-extrafusal

-length

-rate of stretch

-bare

-muscle

-collagen

-Ia afferent: rapidly adapting to stretch of the spindle: monitors change in stretch

-II afferent: slowly adapting to stretch of the spindle: reports on static position

-Conscious: dorsal columns; cross at the medulla (contralateral)

-Unconscious: spinocerebellar; don't cross (ipsilateral)

Definition: Ataxia

-Types?

-loss of coordinated movement

-Types: general proprioceptive, vestibular (special proprioceptive), cerebellar proprioception

-represents a loss of awareness of where thhe limbs are in space

-often occurs with UMN lesions

-loss of postural and placing reactions

-floating hypermetria

-reflects the inability to modulate the gait generating systems in the brain stem

-dysmetria, hypermetria, head tremors, truncal sway, base wide stance

-Muscle spindles: Ia fibers monitor change in length (rapidly adapt) and group II fibers monitor static length, gamma motor neurons cause the intrafusal fibers to contract in concert with the muscle (alpha motor neuron)

-Golgi tendon organ: muscle tension, slowly adapting

-Merkel's: monitor light sustained touch (reading Braille)

-Meissner's: monitor light fluttering touch (feather)

-Pacinian: deep, vibrating touch

-Ruffini: deep sustained

-free

-high

-fibers that carry signal from periphery

-A delta: thermal and mechanical

-C fibers: polymodal

-myelinated

-smaller and unmyelinated

-sharp, fast

-dull, longer

-interneurons

-dorsal

-fast

-substance P

-slower

Definition: Hyperalgesia

-how does this occur?

-repeated stimulation results in an increased sensitivity (lower htreshold) for subsequent noxious stimulation

-local release of inflammatory chemical mediactors that lower the threshold of the nerve endings

-occurs in dorsal horn as an immediate response to high levels of afferent activity (inc dorsal horn discharges with repeated low intensity stimulation)

-response to glutamate

Definition: Allodynia

-how is this clinically relevant?

-when a previously inncocuous stimulus to seem painful

-main reason for using preemptive analgesia

nociceptive sensory input (mechanical/tactile input) such as Αβ fibers can reduce pain

(rubbing or shaking the boo boo makes it better)

-second

-dorsal

-cross

-spinal cord

-thalamus

-free receptors

-free receptors

-dorsal

-medulla

-cross

-thalamus

-somatosensory cortex

-encapsulated receptors

-Nociceptive: when you give a stimulus

-Neuropathic Pain: when you just have a pain neuron being turned on withoit actual stimulus

-Visceral Pain: same pain but starts from visceral organs (tracts same as cutaneous pain, can perceive visceral as cutaneous)

-endolymph

-high K+

-low Na+

-high Na+

-low K+

-in steriovilli and basolateral mem

-40 mV across hari cell mem

-hairs bend, direction of bending determines if K channels open or close (depolarized or hyperpolarized)

-voltage gated Ca+ channels open, excitatory neurotransmitter released, glutamate or aspartate

-AP at afferent sensory neuron

-chambers housing otolithic organs, semicircular canals (cochlea=auditory) that contain hair cells in different planes

-filled with endolymph, hair cells in a gelatinous sybstance in otolithic mem

-rotation

-tilting

-changes in relationship to gravity

-UMN down spinal cord

-vestibulospinal tract ipsilateral

-excite and inhibit extensor and flexors in coordinated fashion

1) to motor nuclei of CN III, IV, and VI in brainstem: eye movement

2) To thalamus, then cortex: conscious awareness of balance

3) To emetic center: vomit

4) To cerebellum: for fine-tuning

-head tilt, ventral ear towards lesion

-lean or fall towards lesion

-circling towards lesion

-asymmetric ataxia, no loss of strength

-postural reactions normal

-nystagmus

NO LOSS OF STRENGTH