I

Smell

II 

vision 

moves eye up and down, medially; raises upper eyelid

adjusts lens shape, constricts pupil 

moves eye down and medially 

V 

facial sensation, chewing, sensation from temporomandibular joint 

VI

abducts eye 

VII 

facial expression, salivation, taste, tears, closes eyes

X

regulates visera, swallowing, speech, taste 

XI 

moves head, elevates shoulders 

XII

moves tongue 

afferent neurons 

(cranial) 

optic (pupillary, consenual, accomodation reflexes)

trigeminal (masseter, corneal reflexes)

glossopharyngeal (gag, swallowing reflexes)

efferent neurons

(cranial) 

oculomotor (pupillary, consensual, accomodation reflexes)

trigeminal (masseter reflex) 

facial (corneal reflex)

vagus (gag, swallowing reflex) 

levator palpebrae

superioris

superior rectus

medial rectus 

inferior oblique 

pupillary sphincter

ciliary 

if eye adducted, pupil up;

if eye abducted,rotates eye

if eye adducted, pupil down and in

if eye abducted, rotates eye 

oral 

pharyngeal/laryngeal

esophogeal 

Food in mouth, lips close VII

Jaw, cheek and tongue movement manipulate food (V, VII, XII)

Tongue moves food to Pharynx entrance (XII) 

larynx closes (X) 

swallow reflex triggers (IX) 

-food moves into pharynx (IX)

-soft palate rises to block food from nasal cavity (X) 

-epiglottis covers trachea to prevent food from entering -lungs (X) 

-peristalsis moves food to entrance of esophagus, spincter opens, food moves into esophagus (X) 

Esophogeal (phase) 

drooping of eyelid 

occurs because of damage to oculomotor nerve 

double vision 

occurs because of damage to the oculomotor nerve 

 Spinal Cord, dorsal and ventral roots, spinal nerves, meninges 

A bundle of connective tissue and glia that connects the end of the cord to the coccyx 

Axons leaving the anterolateral cord in small groups, sending information to the periphery

: Contains motor Axons

 contain sensory axons

Dorsal and Ventral roots join to form the spinal nerve (consists of all sensory and motor axons connected with a segment of the cord) 

emerges between C7 and T1 vertebrae

 the spinal nerve splits into two rami after it transits through the intervertebral foramen; this marks the end of the spinal region and the beginning of the peripheral nervous system. 

 innervates skeletal, muscular and cutaneous areas of the limbs and of the anterior and lateral trunk

 innervates the paravertebral muscles, posterior part of the vertebrae, overlying cutaneous areas. 

 axons that begin and end within the spinal cord; adjacent to the gray matter

 cells with long axons connecting the spinal cord with the brain

processes sensory information;contains endings of first order Neurons and cell bodies of second order neurons for the spinothalamic pathway 

autonomic information (preganglionic); present only at T1-L2 

The specific movement pattern connected with withdrawal reflex. 

- decreases activity in an antagonist when agonist is active. 

-provided by type Ia, cutaneous and joint afferents, interneurons and corticospinal, rubrospinal and vestibulospinal tracts. 

-inhibits agonist and synergists, disinhibiting the antagonist 

 interneurons that produce recurrent inhibition 

-stimulated by collateral branches of alpha motor neurons

 branch axon from an alpha motor neuron that turns back towards its own cell body. 

requires afferents, T11-L2 (efferent sympathetic) and S2-S4 (efferent 

parasympathetic) cord levels 

inhibits pontine urination center; causes pelvic floor muscles to contract to hold in urine.  

 signals sacral urination to empty if not inhibited

 relax the bladder wall and constrict the internal sphincter  

 bladder wall contract and internal sphincter opens

 constrict/open external sphincter 

 compresses the bladder neck, assisting in the external sphincter preventing urination. 

-function at the level of spinal cord segment 

-Lesion: interferes with function only at the level of that segment 

-symptoms: loss of sensory information connected with that dermatome segment; myotome and sclerotome information 

- convey ascending and descending information  

-lesion: interrupt vertical tracts, result in loss of function below the lesion 

-autonomic symptoms: problems regulating blood pressure, sweating, bladder and bowel control. 

-ipsilateral if dorsal column is involved

-contralateral if spinothalamic tract is involved 

UMN signs: paralysis, spasticity, muscle hypertonia 

interrupt ascending spinothalamic tracts and descending motor tracts, damages somas of LMNs 

-pain, sensation and motor control 

- usually occurs at the cervical layer 

-loss of pain and tempurature at the level of the lesion

-impair upper limb motor function 

- results from a hemisection of the cord 

-loss of ipsilateral, Include loss of LMN and sensations, voluntary motor control, conscious proprioception, discriminative touch. 

-pain and temperature are lost contralaterally 

- damage to the lumbar and/or sacral roots 

-sensory imparement, flaccid paresis/paralysis of Lower Limb, bladder and bowel. 

-during development, the vertebral column grows longer than the spinal cord. 

-stretches spinal cord 

-low back/limb pain, difficulty walking, lordosis, scoliosis, problems with bowel and bladder, foot deformities. 

-UMN signs: abnormal reflexes, paresis, change in skeletal muscle

-signs: tuft of hair, hemangioma or buldge of fatty mass. 

-lesion above the sacral level, produce signs similar to UMN lesions 

-lesions S2-S4, produce signs similar to LMN lesions 

-complete lesions at level S2-S4 or afferent or parasympathetic efferents, produce flaccid, paralyzed bladder. 

-complete lesion above the sacral level affect descending axons; results in hypertonic, hyperreflexive bladder. 

Adjusts activity in the descending UMNs; influence movement via pathways through the thalamus to motor areas 

Cortical Motor Area

-produces excitation of the striatum by delivering the transmitter glutamate 

-provides the output of the basal ganglia motor circuit

- the output nuclei provide the appropriate level of inhibition to target nuclei.

-goes to motor areas of the cerebral cortex (via motor thalamus), PPN, and midbrain locomotor region

Excitatory: Glutamate

Inhibitory: Dopamine 

Motor Thalamus ---- motor cortex ---- (corticospinal, corticobrainstem, corticopontine tracts) ---- LMNs --- voluntary muscle 

- provides normal level of facilitation to the LMNs that innervate voluntary muscle

Pedunculopontine nucleus VL -- reticulospinal tracts -- LMNs -- postural and girdle M. 

- provides normal level of facilitation to the LMNs that innervate postural and girdle muscles; control muscle tone 

Midbrain Locomotor Region -- reticulospinal--stepping pattern gen. -- LMNs -- walking

-activate stepping pattern generators, facilitating walking or running 

excessive inhibition. E.g. Parkinson's 

-characterized by akinesia/hypokinesia, rigidity, freezing during movement, visuoperceptive impairments, postural instability, resting tremor 

increased resistance to movement in all muscles. 

 absence of movement 

deficits in using visual information to guide movement 

 different from Alzheimer's in that it affects the ability to plan, maintain goal orientation and make decisions. 

presence of both action and resting tremors 

-rhythmic firing of neuron groups in the subthalamic nucleus is correlated w/tremor. 

Pathology in Parkinson's 

-Due to death of dopamine-producing cells in the substantia nigra compacta and acetylcholine-producing cells in the PPN 

alternating periods of near normal mobility w/immobility, due to the use of L-Dopa. 

-inadequate inhibition 

Huntington's Disease 

 Consists of involuntary, jerky, rapid movements and dementia

-autosomal dominant hereditary 

-causes degeneration in many brain areas, mostly the striatum and cerebral cortex. 

genetic, usually nonprogressive, movement disorders characterized by involuntary sustained muscle contractions causing abnormal postures or twisting. 

-caused by abnormal proteins in the pedunculopontine nucleus 

Coordinates movement and postural control by comparing actual motor output with intended movement and then adjusting movement as necessary.  

 deliver information regarding intended movements to the cerebellum; synapse in the pontine neuclei 

Anterior spinocerebellar

rosterospinocerebellar 

Signals from the spinal cord, reticular formation, vestibular system and pontine nuclei

- convey information about somatosensory, arousal,equilibrium, and cerebral cortex motor info.

Signals from the inferior olivary nucleus in the medulla. 

-convey information about movement error

afferent

Balance

-Functional name for the flocculonodular lobe. 

 coordination (corticospinal, ruberospinal and corticobrainstem tracts) planning, timing 

- movement disorder common to all cerebellar lesions. 

-uncoordinated voluntary movements

-Vermal and flocculonodular lesions: truncal ataxia

-Paravermal lesions: gait and limb ataxia

-lateral cerebellar lesions: hand ataxia

 nystagmus, dysequilibrium, difficulty maintaining sitting and standing balance

-Paravermal and cerebrocelebellar lesions

 ataxic gait; Chronic alcoholism can damage this part of the cerebellum. 

Dysdiadochokinesia: inability to rapidly alternate movements 

Dysmetria: inability to accurately move an intended distance

Action tremor: shaking of the limbs during voluntary movement (agonist is prolonged, antagonist is delayed)

maintaining a fixed position of one joint while another joint is moving. used to compensate for action tremor. 

: interfere with coordination of fine finger movement. 

orientation and balance 

adjustment of the body and head to vertical

orientation comes from (somatosensory, visual and vestibular information) 

ability to maintain the center of mass relative to the base of support. 

 posture is obtained by central commands ; 

central commands are mediated by: reticulospinal, vestibulospinal and medial corticospinal tracts. 

 information about the state of the system

: anticipatory motor impulses that prepare body for movement.

elicited by head and neck rotation to the right or left; limbs on the nose side extended, limbs on the skull side flexed. 

 Flexion of the upper limbs and extension of the lower limbs when neck is flexed. 

When head is tilted back; upper limbs flex and lower limbs extend; because vestibular and neck reflexes oppose eachother, we are not compelled to move our limbs when shaking or nodding the head. 

determines sensory organization and muscle coordination (how postural adjustments are coordinated) 

controlled by brainstem and spinal regions

Cerebral cortex: goal orientation and control of ankle movement 

Basal Ganglia: governs generation of force

Cerebellum: timing, coordination, error correction

Brainstem descending tracts: adjust strength of muscle contraction by: direct connection w/LMNs and adjusted transmission in spinal reflex pathways. 

Controlled by cerebral cortex; vision (feedforward and feedback) and somatosensation 

Action Stream: stream of visual information used for movement. 

proprioception: used to prepare for movement and provide information concerning movement error. 

 stream of visual information used for movement. 

used to prepare for movement and provide information concerning movement error. 

Slow involuntary writhing movements characteristic of cerebral palsy 

 due to somatosensory loss below the neck; only one joint will move at a time. 

anterior part of frontal lobe: makes decisions

 motor planning areas: activate 

control circuits: consist of the cerebellum and the basal ganglia; regulate the activity in upper motor neuron tracts; adjust activity in the descending tracts resulting in excitatory or inhibitory motor neurons.  

upper motor neurons tracts: deliver signals to spinal interneurons and lower motor neurons. 

lower motor neuron tracts: transmit information to skeletal muscle, elicit contraction of muscle fibers  

 brain to spinal cord to muscle 

deliver information from the brain to motor neurons in the spinal cord or brain stem. 

 controls automatic skeletal muscle activity.

: control fractioned movement of the limbs and face; independent contractions of a single muscle.

the ability to activate individual muscles independently of other muscles. ex. flex only the index finger when typing. 

tracts decending from the brainstem

-enhance activity of interneurons and LMNs in the spinal cord 

excitable, contractile, extensile and elastic. 

the resistance to stretch in resting muscle. 

special projections of myosin (myosin head) that connects with the actin

causes stiffening and contracture. Full ROM cannot happen or muscle will rupture. 

-- if muscle is immobilized in lengthened position the muscle will add new sarcomeres

simultaneous contraction of antagonist muscles. This stabilizes joints and enables precise movements. ex. threading a needle. 

large cell bodies and large myelinated axons; project to extrafusal skeletal muscle. 

 alpha and gamma neurons functioning simultaneously. 

 an alpha motor neuron and the muscle fiber it innervates; classified as slow twitch or fast twitch. 

 slow conducting alpha neurons innervate slow twitch muscles fibers. 

fast conducting alpha motor neurons innervate fast twitch muscle fibers. 

coordinated muscular action; type II afferents; 

 example, a person with a UMN lesion, cannot flex shoulder without simultaneously, obligatory flexion of the elbow. 

proprioceptive body schema: spinal cord creates a complete proprioceptive model; the body in time and space; used to plan and adapt movement. 

 registers tendon tension; Ib afferents; adjust muscle contraction

adaptable  network of spinal interneurons that activate lower motor neurons to elicit alternating flexion and extension of the hips and knees; conveyed in the anterior commissure of the spinal cord. 

 indicated that the response is brief;   

Ia afferents transmit action potential to the spinal cord

release neurotransmitter at synapses w/alpha motor neurons.

alpha motor neuron depolarizes

action potential propagates to the neuromuscular junction 

ACh is released and binds w/ muscle receptor

muscle membrane depolarizes

muscle contracts. 

quick response to stretch (there is only one synapse between the afferent and efferent neurons). 

response lasting as long as the stimulus. Only present following UMN lesion. 

in response to cutaneous sensation; ex. stepping on a tac. 

signal lower motor neurons that innervate postural and girdle muscles; descend in the anterior column of the spinal cord; synapse with LMNs located in the anteromedial gray matter; without conscious effort; ex. turn to hear a noise.

facilitates bilateral lower motor neurons innervating postural and gross limb movement through the entire body; coordinating muscle activity of the trunk; postural adjustments, reaching.   

affect activity LMNs controlling the neck and upper back. 

 responsible for gravity information from the vestibular apparatus; maintains center of gravity over the base of support.   

 direct from cortex to the spinal cord (internal capsule and anterior brainstem); axons project ipsilateral, contralateral and bilateral in the spinal cord; medial corticospinal neurons synapse with LMNs and control the Neck, shoulders and trunk muscles; control of posture  

 Unwanted combination of movements due to stroke (lesion) resulting in reticulospinal activity without modification by the collaterals of the corticospinal tracts. 

 Most important pathway controlling voluntary movement; signals lower motor neurons that innervate muscles used for fractionated movement and muscles in the face and neck; 

-arises in motor planning areas and primary motor cortex

-descend in the lateral column; synapse with LMNs in the anterolateral gray matter. 

- in the lower medulla forms the pyramids (junction of the medulla and spinal cord). 

AXONS OF CORTICOSPINAL TRACT

-88% cross the contralateral side 

-10% travel ipsilaterally

 arise in the motor areas of the cerebral cortex; project to cranial nerve nuclei in the brainstem; facilitate LMNs for face, tongue, pharynx, larynx, trapezius and sternocleidomastoid. 

-LMNs to the lower face are controlled contralaterally by corticobrainstem neurons.

-LMNs to the upper face are controlled Bilaterally by corticobrainstem neurons. 

contribute to background levels of excitation in the cord and facilitate local reflexe arcs.

releases norepinephrine; produces tonic facilitation of spinal lower neurons.      

releases seratonin; modulates activity of LMNs 

 not related to specific movements; contribute to poor motor performance when anxiety is high. 

paresis: partial loss of voluntary muscle contraction 

-can be caused by UMN lesion; inadequate facilitation of LMNs 

-commonly follows a stroke

-

paralysis: complete loss of voluntary contraction  

-can be caused by complete lesion of a peripheral nerve 

-hemiplegia: weakness affecting one side of the body 

-paraplegia: body below the arms

-tetraplegia: affects all four limbs 

when an acute UMN lesion interrupts descending motor commands, affected LMNs become inactive and cause loss of descending facilitation and edema affecting the area of the lesion. 

-no stretch reflexes

-muscles are hypotonic

-caused by infection (poliomyelitis), degenerative or vascular disorders, and tumors; causes damage to LMNs 

-loss of reflex

-atrophy

-flaccid paralysis

-fibrillations: rapid, irregular and unsynchronized contraction of muscle fibers 

UMNs can be damaged by spinal cord injuries, spastic cerebral palsy, MS, trauma, or loss of blood supply to part of the brain (stroke) 

-paresis/paralysis

-paresis: occurs in UMN lesions as a consequence of inadequate facilitation of lower motor neurons. common following a stroke because of disruption of bloodflow to the brain. 

-Paralysis: complete loss of voluntary control of muscles; occurs below the level of a complete spinal cord lesion (loss of somatosensory and motor functions) 

-loss of fractional movement

-velocity-dependent hypertonia: limits joint range of motion (toe walking) Caused by muscular changes (myoplasticity) and/or spasticity.  Why is it called velocity dependent? 

-abnormal cocontrations (in spastic cerebral palsy): the simultaneous activation of antagonist muscles that interferes with task performance.  

-abnormal muscle synergies (post stroke)

excessive muscle contraction when muscle spindle is stretched; loss of inhibitory corticospinal input. 

involuntary repeating contraction of a single muscle group. 

an abrupt decrease in resistance when paretic muscle is slowly and passively stretched. 

-weak actin-myocin bonds, contracture and spasticity cause increased resistance to muscle stretch. 

-paresis, abnormal timing of muscle activity, babinski's sign, myoplasticity. 

-peripheral nerve distribution

-paresis or paralysis, sensory loss, abnormal sensation, muscle atrophy, reduced or absent deep tendon reflexes 

Innervate the skeletal, muscular and cutaneous areas of the limbs and the anterior lateral trunk

innervate the paravertebral muscles, posterior parts of the vertebrae, and overlying cutaneous areas. 

-myotomal and/or dermatomal distribution 

-distinguished sensory, autonomic, and motor deficits 

consist of sensory, autonomic and motor axons

Supply skin and subcutaneous tissue; muscular branches supply muscle, tendons and joints. 

-C1-C4

-deep to the sternocledomastoid 

- cutaneous sensory info from the posterior scalp to the clavical; innervates anterior neck muscles and diaphram

 cell bodies in the cervical spinal cord (C3-C5); MOST important single branch from the cervical plexus; ONLY motor supply and main sensory nerve for the diaphragm. 

-C5-T1 

-emerges between the anterior and middle scalene muscles; deep to the clavicle; enters the axilla

-radial; axillary; ulnar; median; musculocutaneous 

-L1 - L4

- forms it the psoas major muscle 

-innervate skin and muscles of the anterior and medial thigh

Saphenous nerve: continues into the leg to innervate the medial leg and foot 

-contains both parasympathetic and somatic motor axons 

spontaneous release of small amounts of ACh. Thought to supply factors necessary for muscle health, although not enough potential to create contraction. 

-Sensory Changes 

Hyperalgesia, Dysesthesia, paresthesia and allodynia 

-Autonomic 

depends on pattern of axonal dysfunction 

-Motor Changes

paresis, paralysis 

 Fasciculations: contractions observable on the skins surface

Fibrillations: contractions of single muscle fiber, not visible on the skin 

-Trophic Changes

 Skin becomes shiny, muscles atrophy, nails become brittle, subcutaneous tissue thickens 

involving One nerve; focal dysfunction

presents asymmetric involvement of individual nerves; two or more nerves; not whole regions  (multiple focal) 

-often seen in diabetes or vasculitis because of ischemia. 

Vasculitis: inflammation of blood vessels. 

generalized disorder that typically presents distally (to proximal) and symmemtrically. regional 

-large axons are the first to be destroyed

-involves sensory, motor, and autonomic fibers 

-often appear in the feet first and then the hands (Stocking/Glove distribution) 

-causes: toxic, metabolic, autoimmune 

-most common (diabetes), then nutritional deficiencies, alcoholism, autoimmune 

paresis of muscle distal to the knee; foot drop; steppage gate; frequent tripping; muscle atrophy. 

loss of myelin limited to the site of injury 

-large diameter; producing motor, discriminative touch, proprioceptive, phasic stretch reflex deficits, neuropathic pain. 

- disrupts axons; wallerian degeneration occurs distal to the lesion. 

-usually arise from crushing of the nerve 

: 

- occurs when nerves are physically divided by excessive stretch or laceration. 

-immediate loss of sensation

-Wallerian degeneration begins DISTALLY 3 to 5 days later 

 tumor of axon and Schwann cells; due to axon spouts growing into a tangled mess because of scar tissue between the stumps. 

Myasthenia Gravis

Botulism (affect stretch reflex)

Both affect release of ACh and cause muscle weakness 

MYOPATHY 

Disorders intrinsic to muscle

-muscular dystrophy