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439 Cards in this Set
- Front
- Back
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Fx of semicircular canals?
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detect ANGULAR acceleration or deceleration in three planes: horizontal, vertical, and lateral simultaneously
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Roll is?
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rotation around the x axis
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Pitch is?
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rotation around the Y axis
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YAW is?
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rotation around the z axis
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YAW stimulates which semicircular canal?
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horizontal
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What 2 positions place the lateral canals in a vertical position?
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1)extending the head backward 60 degrees; 2)lifting head up by 30 degrees w/ a pillow
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Flexing the head 30 degress forward puts the lateral canal in what position?
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horizontal position
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In what direction does the endolymph move in response to the head movement?
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head moves one way and endolymph moves other way
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In the horizontal ampulla, what direction are the cilia orientated in response to the utricle?
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toward the utricle
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In the ampulla that aren't horizontal, that direction are the cilia orientated in response to the utricle?
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away from the utricle
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How are semicircular canals arranged on either side of the head?
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they are functionally paired on either side of the head because they lie in common planes - like a "hula hoop"
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Head movement to the L stimulates?
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afferent firing from L horizontal canal and inhibits firing from R
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Does head movement to L have an effect on the posterior and anterior canals?
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NO because they are not in plane of rotation
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Right anterior canal paired w/?
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left posterior canal
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Right posterior canal paired w/?
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left anterior canal
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Sensory incoming for VOR is?
Motor outgoing for VOR is? |
CN 8
CN 3,4,6 |
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Does VOR have short latency or long?
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short latency due to change in APs in the ampulla; 12 milliseconds
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Is VOR the fastest reflex?
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NO; knee-jerk reflex is the fastest because it has only one synapse
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When head moves R what happens to endolymph and kinocilium?
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endolymph lags behind causing fluid to flow to L; kinocilium on R is stimulated and on L is inhibited
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Clinical tests of the vestibular system check?
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Pons, CN 3, 4, 6
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Warm water induces nystagmus that beats towards?
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warm ear
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Cold water induces nystagmus that beats away from?
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cold ear
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APs decrease or increase in ear with cold water?
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decrease
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How long does caloric nystagmus last?
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as long as there is a temperature gradient
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Rotational testing w/ Barany chair causes nystagmus in what direction? How long does nystagmus last?
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in direction of the chair rotation; 30 seconds
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Optokinetic nystagmus occurs when? How long does it last?
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lights are on and pt can see environment as chair is being turned; lasts as long as the chair is turning because eyes are tracking visual clues
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CN needed for optokinetic nystagmus?
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CN2 is sensory in and CN3,6 is motor out
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Sudden full stop of the rotating Barany chair will cause? In what direction?
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postrotary nystagmus in the direction opposite of chair movement
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What causes postrotary nystagmus?
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sudden stop of head and semicircular canals, but endolymph keeps on moving in direction chair was turning
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What is the most common vestibular disorder?
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benign positional vertigo
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Benign positional vertigo; symptoms?
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otoconia displaced from utricle macula becomes lodged in cupula of the posterior canal; brief episodes of vertigo that coincide w/ changes in body position
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Labyrinthine disease also known as?
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seasickness and space sickness
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Subjective symptoms of labyrinthine disease?
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vertigo, nausea, oscillopsia, anxiety
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Objective symptoms of labyrinthine disease?
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nystagmus, falling or postural deviation, sweating, pallor, vomiting, hypotension
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Acute peripheral vestibulopathy
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spontaneous attack of vertigo of unapparent cause; usually due to infection
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Acute peripheral vestibulopathy includes what 2 diseases?
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acute labyrinthitis, vestibular neuronitis
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Acute peripheral vestibulopathy characterized by?
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vertigo, nausea, and vomiting of acute onset; can last up to 2 wks
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What are two types of drugs that damage the vestibular system?
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aminoglycosides, Gentamyacin
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What CN helps w/ pupillary reflex by controlling sphincter muscles and ciliary muscles?
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CN3
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What CN keeps eyelid up?
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CN3
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CN3 controls which eye muscles?
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superior rectus, medial rectus, inferior rectus, inferior oblique
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What CN controls lateral rectus?
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CN6
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What CN controls superior oblique?
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CN4
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What happens when you contract the superior oblique muscle?
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eyes moves in (intorsion) and downward
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What happens when you contract inferior oblique?
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eye moves outward (extorsion)
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Supranuclear regulation of eye movements found in?
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brainstem, cerebellum, and forebrain including the basal ganglia
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Forebrain contains which eye fields?
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frontal eye fields
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Horizontal eye movement control center?
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Pons
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What nucleus is the horizontal gaze center and what does it control?
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abducens nucleus; controls ipsilateral lateral rectus and contralateral medial rectus
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What is the interconnection between the occulomotor, trochlear, abducens, and vestibular nuclei?
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MLF medial longitudinal fasiculus
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What does the paramedian pontine reticular formation do?
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PPRF provides output to the abducens from higher cortical eye movement control centers
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Lesion of the PPRF or abducens nucleus will cause?
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ipsilateral horizontal gaze palsy; problem w/ moving both eyes in directed gaze
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What CN closes the eyelid?
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CN7
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What has cell bodies for CN3?
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VTA
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Tegmentum contains?
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CN3 cell bodies; reticular formation
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Corneal reflex controlled by?
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CN5, CN7
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"Blink to threat" is which CNs?
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CN2, CN7
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Vertical and vergence eye movement control center is?
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midbrain
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Where are vertical eye movements initiated?
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rostral midbrain reticular formation and pretectal area
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Rostral midbrain reticular area controls?
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superior and inferior rectus muscles and the inferior and superior oblique muscles
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Dorsal region of rostral midbrain reticular area controls?
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upward gaze
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Ventral region of rostral midbrain reticular area controls?
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downward gaze
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Midbrain reticular formation initiates?
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vergence eye movements
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What muscles cause convergence of the eyes?
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medial rectus muscles
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What muscles cause divergence of the eyes?
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lateral rectus muscles
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What controls eye movement for near and far vision?
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descending control from occipital and parietal cortex
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Forebrain centers controlling eye movements send information from cerebral cortex to?
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brainstem centers and the superior colliculi
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Frontal eye fields stimulate?
Generate? |
contralateral PPRF; generate conjugate eye movements to the contralateral side
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Lesion of the frontal eye field causes?
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BOTH eyes to gaze toward lesioned side; eyes look away from paralysis
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Parieto-occipito-temporal cortex stimulates?
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smooth pursuit eye movements in the ipsilateral direction
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If you stimulate the L frontal eye fields in which direction is the conjugate eye movement?
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Right
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What are the two principal types of eye movements?
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eye movements that change the line of sight (usually voluntary); eye movements that keep the retinal image steady (reflex)
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Do eye muscles pull against gravity?
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No; they also always have the same mechanical load
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What is the pulse of innervation?
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phasic increase or burst of neural activity in the occular motor nuclei that is needed to generate a powerful contraction of the extraocular muscles to overcome the viscous resistance associated w/ eye movement
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Amplitude or velocity of eye movement correlated w/?
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duration of the burst or pulse of APs
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What is the fastest of the eye movements?
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saccadic
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What eye movement is ballistic?
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saccadic; can't change course of eye movement in response to subsequent changes in the target during the delay period
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What is the delay time between the appearance of the target of interest and the onset of eye movement?
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200 msec
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Smooth pursuit system generates?
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smooth following movements of the eyes that closely match the pace of the target; keep targets on the fovea
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Humans can't generate smooth pursuit eye movements w/o?
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a target
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What type of lesion leads to ataxic eye movements?
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cerebellum lesions
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What do vergence eye movements do?
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align the fovea of each eye w/ targets located at different distances from the observer
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What is the only type of eye movement that causes eyes to move in opposite directions?
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vergence eye movements
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Near reflex triad consists of?
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convergence of the eyes, accomodation of the lens (PNS), constriction of the pupil (PNS)
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Which 2 CNs operate together to hold images stable on the retina?
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CN2,CN8
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What system used during brief or rapid head movement?
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vestibular system
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What system used during sustained or slow head movement?
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optokinetic system
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What is optokinetic nystagmus composed of?
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a pursuit eye movement to track the moving environment and then reset w/ a fast saccade
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How long does the optokinetic system maintain its affect?
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until the field of vision stops moving
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What acts as a back-up to the VOR?
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optokinetic system
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Lateral axon motor axons terminate?
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on lateral groups of ventral horn motor neurons and interneurons
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Lateral motor systems control movement of?
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extremities - arms, legs, feet, hands
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What are the two tracts in the lateral motor system
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lateral corticospinal tract and rubrospinal tract
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Rubrospinal tract?
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Increasese flexor tone in the upper extremities
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Both lateral motor tracts provide for?
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rapid, dexterous movements at individual joints or digits
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Lesion in lateral motor system first leads to? Then to?
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weakness; hyperreflexia (spasticity)
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If LMNs are gone completely then you get?
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atrophy
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How many "AL" inputs are there for the extremities?
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single input
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LMNs more medial run the?
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trunk
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LMNs more lateral run the?
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extremities
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Why are you not worried about trunk paralysis clinically?
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medial motor systems go bilateral to innervate the trunk
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Medial motor pathways synapse on?
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medial ventral horn motor neurons and interneurons
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Medial motor system controls movements of the?
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trunk; axial and girdle muscles
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Axial and girdle muscles involved in?
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postural tone, balance, orientating movements of the head and neck, automatic gait-related movements
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Medial motor systems descend?
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ipsilaterally and terminate on interneurons; some of whose axons cross the ventral commissure
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Medial motor systems influence axial musculature?
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bilaterally
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What are the 4 tracts in the medial motor system?
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anterior(ventral) corticospinal tract, vestibulospinal tract, reticulospinal tract, tectospinal tract
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Anterior corticospinal tract controls?
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doesn't cross midline; bilateral control of axial and girth muscles
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Lateral vestibulospinal tract runs?
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length of spinal cord; controls extensor tone
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Medial vestibulospinal tract runs?
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ends at cervical cord level; controls head and neck muscles
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Reticulospinal tract controls?
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automatic posture and gait movements
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Tectospinal tract controls?
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ends in the cervical cord; provides coordination of head and eye movement
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Paresis means?
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weakness
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-plegia means?
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no movement
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Paralysis means?
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no movement
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Palsy means?
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can mean weakness or no movement
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Hemi- means?
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one side of body
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Para- means?
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both legs
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Mono- means?
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one limb
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Di- means?
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both sides of body equally affected
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Quadri- or tetra- means?
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all four limbs
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Hemisection of spinal cord can cause?
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Brown-Sequard syndrome
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Brown-Sequard syndrome causes?
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ipsilateral UMN signs; ipsilateral loss of vibration, proprioception, joint position, fine touch; contralateral loss of pain, temperature, itch, and crude touch
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An anterior spinal artery infarct can damage what pathway?
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anterolateral pathways and ventral horn cells
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Damage of anterolateral pathway causes?
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no pain and temperature sensation below the lesion bilaterally
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What water-soluble vitamin is required for myelin formation
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vitamin B12 cobalamine
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Lack of intrinsic factor causes?
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pernicious anemia; also causes tingling and numbness of hands and feet
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Paresthesia is?
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numbness
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What fat soluble vitamin is important for neural tissue?
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vitamin E
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Which has greater degeneration of myelin?
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dorsal column degeneration greater than corticospinal tract degeneration
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What occurs w/ degeneration of cerebral white matter?
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dementia
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What is infectious myelitis?
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inflammation of the spinal cord
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Infectious myelitis includes?
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HIV, Lyme disease, tertiary syphilis, and poliomyelitis
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Inflammatory myelitis includes?
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MS, Lupus, postinfectious myelitis
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Poliomyelitis affects?
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affects "AL"
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Amyotrophic lateral sclerosis (ALS) affects?
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can affect LMNs and UMNs
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Lou Gehrig's Disease is a disease of?
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motor neurons
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What is Guillain-Barre Syndrome?
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acute inflammatory demyelinating polyneuropathy which is an immune mediated demyelination of peripheral nerves
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What are the three main brainstem sections?
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midbrain, pons, medulla
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What is the tectum?
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"roof;" composed of the superior and inferior colliculi which lie dorsal to the cerebral aqueduct
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What is the tegmentum?
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"covering;" lies ventral to the aqueduct (midbrain) and vertral to the 4th ventricle in the pons and medulla
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Brain stem tegmentum is the location of?
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main bulk of the brain stem nuclei and reticular formation
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What is the reticular formation?
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groups of neuronal nuclei and meshwork of neuronal axons
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What is the basis of the brain stem?
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most ventral part of the brain stem (pons and midbrain only)
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What is located in the basis?
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location of the large collection of fibers and tracts: corticobulbar, corticospinal, corticopontine tracts
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What are the three CNs not associated w/ the brain stem?
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CN1, CN2, CN11
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CN1 and CN2 associated w/?
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forebrain
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CN11 associated w/?
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cervical spinal cord
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What 2 CNs associated w/ the midbrain?
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CN3, CN4
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What 4 CNs are associated w/ the pons?
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CN5, CN6, CN7, CN8
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What 3 CNs associated w/ the medulla?
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CN9, CN10, CN12
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What 3 CNs are sensory?
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CN1, CN2, CN8
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What sensory CN associated w/ the brain stem?
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CN8
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What are the 5 motor CNs?
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CN3, CN4, CN6, CN11, CN12
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What motor CNs are associated w/ the brain stem?
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CN3, CN4, CN6, CN12
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What are the 4 mixed CNs?
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CN5, CN7, CN9, CN10
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CN9 and CN10 do?
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sensory and motor for viscera; parasympathetic NS
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CN7 is mainly?
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motor
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CN5 is mainly?
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sensory
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CN 12 does?
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tongue
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Where are PNS preganglionic neuronal cell bodies for CN3?
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Edinger-Westphal nucleus - MIDBRAIN
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Where are PNS preganglionic neuronal cell bodies for CN7?
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Superior salivatory nucleus -PONS
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Where are PNS preganglionic neuronal cell bodies for CN9?
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Inferior salivatory nucleus -
MEDULLA |
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Where are PNS preganglionic neuronal cell bodies for CN10?
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Dorsal motor nucleus of CN10 - MEDULLA
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The postganglionic neurons of CNs 3,7,9,10 innervate?
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glands, smooth muscle, and cardiac about the splenic flexure (NOT striated muscle)
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What CNs provide the predominant autonomic tone to the head and thoracoabdominal viscera?
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CNs 3,7,9,10
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Postganglionic parasympathetic neuron cell bodies are found inside or outside the CNS?
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outside
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Where are the postganglionic parasympathetic neurons located for CN3?
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ciliary ganglion
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Where are the postganglionic parasympathetic neurons located for CN7?
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Sphenopalatine ganglion and submandibular ganglion
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Ciliary ganglion axons project to?
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eye ciliary muscle and constrictor muscle of the iris
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Sphenopalatine ganglion axons project to?
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lacrimal glands and nasal mucosa
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Submandibular ganglion axons project to?
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submandibular and submaxillary salivary glands
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Where are the postganglionic parasympathetic neuron cell bodies located for CN9?
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otic ganglion
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Otic ganglion axons project to?
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parotid gland
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Where are the postganglionic parasympathetic neuron cell bodies located for CN10?
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various terminal ganglion
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Axons for various terminal ganglion project to?
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effector organs
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Sympathetic nervous system innervates?
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eyes, face, scalp
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Does the descending tract of the SNS from the hypothalamus cross the midline?
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NO
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Where are all of the SNS preganglionic cell bodies located?
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IML of spinal cord; rexed lamina 7; T1-L3
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SNS preganglionic cell bodies innervating the head are found?
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in the IML of T1-T2
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Where are the SNS postganglionic cell bodies located?
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superior cervical ganglion
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A lesion of the sympathetic pathway to the head will cause?
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ipsilateral Horner's Syndrome
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What are the three classic signs of Horner's Syndrome?
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Miosis, ptosis, anhidrosis
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Miosis is?
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decreased pupil size
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Anhidrosis is?
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lack of sweating on the face and neck
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Does UMN lesion cause weakness?
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YES
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Does LMN lesion cause weakness?
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YES
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Does LMN lesion cause atrophy?
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YES
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Does UMN lesion cause atrophy?
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NO
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Does UMN lesion cause fasiculations?
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NO
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Does LMN lesion cause fasiculations?
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YES
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What happens to reflexes w/ UMN lesion?
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increased
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What happens to reflexes w/ LMN lesion?
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decreased
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What happens to tone w/ UMN lesion?
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increased
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What happens to tone w/ LMN lesion?
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decreased
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What are the 5 main neural tracts coursing through the brain stem?
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medial lemniscus, anterolateral system, corticospinal tract, descending hypothalamic SNS fibers, medial longitudinal fasiculus
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Medial lemniscus is?
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sensory ascending
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Anterolateral system is?
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sensory ascending for pain, temperature, itch
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Corticospinal tract is?
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motor descending
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Descending hypothalamic SNS fibers are?
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motor ANS descending
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Brain stem lesions producing ipsilateral Horner's Syndrome may also result in?
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contralateral loss of pain and temperature sensations from the limbs and body
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MLF goes through?
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Pons and Midbrain
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What keeps eyeball movements yoked together?
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MLF
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Brain stem lesions of the MLF produce?
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internuclear opthalmoplegia (INO) and disrupts the VOR
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With INO the eye on the lesioned side can't?
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adduct (innervation to the medial rectus lesioned)
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What can cause lesions to the MLF?
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multiple sclerosis plaques, pontine infarcts, or neoplasms
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UMN fibers originate in?
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motor cortex
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UMN fibers terminate?
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motor CN nuclei in the pons and medulla
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What innervates all CN nuclei that causes skeletal muscle to contract?
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UMN
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What CNs have alpha motor neurons?
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CNs 12,11,7,5
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Corticobulbar innervation of the LMN in CNs is?
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Bilateral
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Each LMN of the brain stem receives input from axons arising from?
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both the R and L cerebral motor cortex
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What CN is the exception for bilateral innervation?
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CN7; facial nerve LMN to the face receives only contralateral UMN innervation
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What is Bell's Palsy?
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facial nerve lesion (LMN) will cause ipsilateral total (upper and lower) face paralysis
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Corticobulbar lesion (UMN) will cause?
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only lower face palsy contralateral to the lesion
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Cell bodies for CN7 are located?
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tegmentum
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Does an UMN lesion allow you to wrinkle forehead and close eyelid? Why?
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YES; bilateral innervation
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Does a LMN lesion allow you to wrinkle forehead and close eyelid? Why?
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NO; no bilateral innervation
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The nuclei of the CNs are arranged in?
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discrete, discontinous, cell columns
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Cell bodies with motor fx are found near?
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midline
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Cell bodies with sensory fx are found near?
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lateral border of brain stem
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Cell bodies of CNs w/ mixed motor and sensory visceral fx are found near?
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sulcus limitans
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Rostral solitary nucleus has what input?
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taste input
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Caudal solitary nucleus has what input?
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autonomic sensory input
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What can you see in the spinomedullary junction section?
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pyramidal tract decussation
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What can you see in the caudal medulla section?
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dorsal column nuclei - internal arcuate fibers (second order neuron decussation)
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What can you see in the rostral medulla section?
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inferior olivary nucleus and CN12 nucleus
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What can you see in the caudal pons section?
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level of genu of CN7
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What can you see in the rostral midbrain section?
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level of the superior colliculus and CN3
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What connects the medulla to the cerebellum?
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inferior cerebellar peduncle
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What contains the autonomic centers for respiratory, cardiovascular, and GI control?
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medulla
|
|
|
CN12 is?
|
motor nerve for the tongue
|
|
|
Nerve fibers for CN12 exit?
|
between the inferior olive and corticospinal tract
|
|
|
Lesion of LMN for the tongue causes?
|
tongue to point to the side of the lesioned upon protrusion
|
|
|
Lesion of UMN for the tongue causes?
|
tongue to point away from the lesioned (affected) side upon protrusion
|
|
|
CN11 is?
|
motor nerve that moves head to opposite side and rotates and elevates the scapula
|
|
|
Cell bodies for CN11 are located?
|
in upper 5-6 cervical segments of the spinal cord in the spinal accessory nucleus
|
|
|
Spinal accessory nucleus protrudes?
|
between the dorsal and ventral horns of the spinal cord
|
|
|
Lesion of CN11 causes?
|
weakness in turning head to the contralateral side against resistance and ipsilateral shoulder drop
|
|
|
CN10 innervates which skeletal muscles?
|
pharyngeal and laryngeal muscles (old gill arches)
|
|
|
CN10 motor nucleus is?
|
nucleus ambiguus
|
|
|
CN10 controls muscles for?
|
swallowing (gag reflex) and phonation
|
|
|
Other motor innervation for CN10 is?
|
parasympathetic innervation of smooth muscle and cardiac muscle
|
|
|
What is the nucleus for parasympathetic innervation?
|
dorsal motor nucleus of CN10
|
|
|
Sensory for CN10 is?
|
taste from epiglottis and pharynx and aortic arch chemo- and baro- receptors
|
|
|
What is the CN10 nucleus for taste from epiglottis and pharynx?
|
rostral nucleus solitarius - gustatory
|
|
|
What is the CN10 nucleus for aortic arch chemo- and baro- receptors?
|
caudal nucleus solitarius - cardiorespiratory
|
|
|
The third sensory function of CN10 is?
|
somatic sensation from meninges and external ear
|
|
|
Primary sensory neurons for meninges and external ear located in?
|
superior vagal ganglion
|
|
|
Second order sensory project neuron for meninges and external ear located in?
|
spinal trigeminal nuclei
|
|
|
Lesion of CN10 causes?
|
dysphagia, loss of gag reflex, cough, dysarthria w/ hoarseness w/ fixed vocal cord
|
|
|
Bilateral lesion of the vagus is?
|
fatal w/ complete laryngeal paralysis (rare)
|
|
|
Motor for CN9 is? Nucleus?
|
stylopharyngeus muscle and parasympathetic innervation of parotid gland; nucleus ambiguus; inferior salivatory nucleus
|
|
|
What is the fx of the stylopharyngeus muscle?
|
elevates pharynx during talking and swallowing (part of gag reflex w/ vagus)
|
|
|
One sensory function for CN9?Nucleus?
|
taste from posterior 1/3 of tongue; rostral solitary "gustatory" nucleus w/ vagus
|
|
|
Second sensory function for CN9? Nucleus?
|
chemo- and baro- receptors in carotid body and carotid sinus; caudal solitarius
"cardiorespiratory" nucleus w/ vagus |
|
|
Third sensory function of CN9? Nucleus?
|
general somatic sensation from middle ear, outer ear, pharynx, and posterior 1/3 of tongue; superior glossopharyngeal ganglion for primary neuron; spinal trigeminal nuclei for second order neuron assiciated w/ CN10
|
|
|
Lesion of CN9 causes?
|
loss of gag reflex w/ CN10
|
|
|
One of the earliest signs of Bell's Palsy is?
|
outer ear pain
|
|
|
What synapses in VPL?
|
Body
|
|
|
What synapses in VPM?
|
Head
|
|
|
What is found in the pyramids?
|
corticospinal tract; upper motor neuron axons from ipsilateral M1 cerebral cortex
|
|
|
What happens in the pyramidal decussation?
|
corticospinal tract motor neuron axons cross to the contralateral side of the body
|
|
|
What happens in the anterolateral (ALS) system?
|
spinothalamic, spinoreticular, and spinomesencephalic tracts, sensory projection neurons encoding pain, itch, and temperature from the contralateral body
|
|
|
What happens in fasiculus and nucleus gracilis?
|
sensory, primary afferent axons encoding proprioception, fine touch, and vibration BELOW T6 from the ipsilateral body
|
|
|
Axons from below T6 will synapse with?
|
projection neuron cell bodies in the nucleus gracilis and cross over in the internal arcuate fibers to become the medial lemniscus
|
|
|
What happens in the fasiculus and nucleus cuneatus?
|
sensory primary afferent axons encoding proprioception, fine touch, and vibration ABOVE T6 from the ipsilateral body
|
|
|
Axons from above T6 will synapse with?
|
projection neuron cell bodies in the nucleus cuneatus and cross over in the internal arcuate fibers to become the medial lemniscus
|
|
|
What happens in the spinal trigeminal tract and nucleus?
|
primary sensory axons from ipsilateral face provide pain, temperature, itch, and crude touch sensation for the face, mouth, anterior 2/3 tongue, nasal sinuses, and supratentorial dura as well as encoding pain and temperature for the outer ear on CNs 7, 9, 10
|
|
|
Spinal trigeminal nucleus projection neuron cell bodies send axons which?
|
cross the midline to travel in the trigeminothalamic tract and synapse in the VPM nucleus of the thalamus
|
|
|
What is the level of the belly button?
|
T10
|
|
|
What is found in the medial lemniscus?
|
sensory projection neurons encoding proprioception, fine touch, and vibration from the contralateral body
|
|
|
What happens if internal arcuate fibers are lesioned before they decussate?
|
ipsilateral damage
|
|
|
What happens if internal arcuate fibers are lesioned after they decussate?
|
contralateral damage
|
|
|
What is the most common site of stroke in the brain stem?
|
rostral medulla
|
|
|
What is found in the vestibular nuclei?
|
sensory neurons from the ipsilateral vestibular membranous labyrinth encoding acceleration (CN8 vestibular portion)
|
|
|
What is found in the solitary nucleus and tract?
|
sensory fibers from the tongue encoding taste (CN7, 9, 10) with cardio-respiratory information from carotid artery and aortic arch (CN9, 10)
|
|
|
What is found in the hypoglossal nucleus?
|
LMNs for the ipsilateral half of the tongue (CN12)
|
|
|
What is found in the ambiguus nucleus?
|
LMNs for muscles in pharynx and larynx (CN9, 10)
|
|
|
What is found in the dorsal motor nucleus of the vagus?
|
motor preganglionic fibers to viscera in the thorax and abdomen (CN10)
|
|
|
What does the inferior olivary nucleus give rise to?
|
clmibing fibers that innervate the contralateral half of the cerebellum
|
|
|
What is found in the inferior cerebellar peduncle?
|
cerebellar afferents including crossed olivocerebellar fibers which become climbing fibers in the cerebellar cortex
|
|
|
What happens if there is a lesion in the descending sympathetic tract from the hypothalamus?
|
ipsilateral Horner's syndrome and contralateral loss of pain and touch sensation
|
|
|
What CN nuclei are located in the pons?
|
CN5,6,7,8 nuclei
|
|
|
What is located on the dorsal surface of the pons?
|
4th ventricle
|
|
|
What connects nuclei in the pons base to the cerebellum?
|
large thick middle cerebellar peduncles
|
|
|
What 3 fiber tracts are located in the base of the pons?
|
corticospinal, corticopontine, corticonuclear(bulbar)
|
|
|
The head has bilateral input except for the?
|
lower face
|
|
|
The ascending auditory pathway is the lateral or medial lemniscus?
|
lateral
|
|
|
What does the lateral lemniscus tract carry?
|
the bulk of ascending auditory pathways from both cochlear nuclei to the inferior colliculus of the midbrain
|
|
|
Facial nerve fibers curve around?
|
abducens nucleus
|
|
|
Can pts with Bell's Palsy wrinkle their forehead?
|
NO
|
|
|
What is "central 7?"
|
UMN lesion of CN7
|
|
|
What are the symptoms with "central seven?"
|
weakness in the inferior contralateral face
|
|
|
What CN keeps the eyes yoked together for horizontal eye movements?
|
CN6
|
|
|
What is the center for control of horizontal eye movements?
|
PPRF
|
|
|
Innervating the contralateral PPRF causes?
|
frontal eye fields to generate fast conjugate eye movements to the contralateral side
|
|
|
Lesion of the abducens nerve will cause?
|
diplopia - CN6 palsy ipsilateral
|
|
|
Lesion of the abducens nucleus will cause?
|
ipsilateral, lateral gaze palsy
|
|
|
Lesion of the abducens nucleus and ipsilateral MLF will cause?
|
ipsilateral lateral gaze palsy and internuclear opthalmoplegia
|
|
|
Lesion of the cerebral hemisphere will cause gaze to what side?
|
side of the lesion
|
|
|
Motor nucleus of CN5 runs from?
|
upper to mid pons
|
|
|
Sensory nucleus of CN5 runs from?
|
midbrain to upper cervical spinal cord
|
|
|
What is motor nerve for muscles of mastication?
|
trigeminal (CN5)
|
|
|
Which trigeminal nucleus does proprioception?
|
mesencephalic trigeminal nucleus
|
|
|
Which trigeminal nucleus does fine touch and dental pressure?
|
chief or major trigeminal sensory nucleus
|
|
|
Which trigeminal nucleus does crude touch, pain, and temperature?
|
spinal trigeminal nucleus
|
|
|
What is found in the abducens nucleus?
|
LMNs innervating the ipsilateral lateral rectus muscle of the eye
|
|
|
What is important about the internal genu of the facial nerve?
|
point where the LMNs for the ipsilateral half of the face wrap around the abducens nucleus
|
|
|
What does the facial nucleus contain?
|
LMNs innervating muscles of the face
|
|
|
What does the vestibular nuclei contain?
|
sensory neurons from the vestibular portion of the membranous labyrinth encoding acceleration
|
|
|
What does the MLF contain?
|
motor tract involved with eye movement coordination
|
|
|
What do the axons from the pontine nuclei do?
|
each one sends an axon across the midline to the middle cerebellar peduncle
|
|
|
What CN nuclei are located in the midbrain?
|
CN3, 4 nuclei
|
|
|
What does the inferior colliculi process?
|
auditory information received bilaterally from the cochlear nuclei from the lateral lemniscus
|
|
|
What does the superior colliculi do?
|
processes and coordinates eye movements
|
|
|
What does the pretectal region contain?
|
interneurons involved in the pupillary light reflex
|
|
|
What is the largest nucleus in the midbrain?
|
substantia nigra
|
|
|
Lesion to CN4 will cause?
|
diplopia and weakness while looking down with abducted eye
|
|
|
Lesion to CN3 will cause?
|
diagonal diplopia and loss of horizontal gaze
|
|
|
CN3 PNS innervates which 2 intraocular muscles?
|
Sphincter pupillae muscle and ciliary muscle
|
|
|
Sphincter pupillae muscle does what?
|
contracts the muscle of the iris and constricts the pupil - MIOSIS
|
|
|
What is mydriasis? What causes it?
|
pupil dilation; SNS
|
|
|
What does the ciliary muscle do?
|
contraction causes the lens to increase its curvature
|
|
|
Lesion to the CN3 component will cause?
|
loss of near vision response and ptosis with dilated pupil and loss of light reflex; eyeball is down and out at rest
|
|
|
What is located in the cerebral peduncles?
|
descending corticospinal, corticobulbar, and corticopontine fibers from the ipsilateral cortex
|
|
|
What is found in the mesencephalic trigeminal nucleus?
|
sensory proprioception from muscles of mastication, tongue, and extraocular muscles (CN5)
|
|
|
What is found in the ventral tegmental areas?
|
dopaminergic neurons projecting to nucleus accumbens and limbic system
|
|
|
What is found in the superior colliculus?
|
integration of eye movement control
|
|
|
What is found in the periaqueductal gray?
|
site of origin of descending pain control pathway
|
|
|
What are the red nuclei?
|
motor nucleus that projects to alpha spinal motor neurons
|
|
|
What is the substantia nigra?
|
part of the motor control by the basal ganglia
|
|
|
Where do the substantia nigra axons terminate?
|
in the caudate nucleus and putamen
|
|
|
What is found in the Edinger Westphal nucleus?
|
PNS preganglionic innervation of the ciliary muscles of the lens and pupillary constrictor muscle
|
|
|
What is found in the medial geniculate nucleus of the thalamus?
|
auditory pathway to the primary cortex
|
|
|
What is found in the lateral geniculate nucleus of the thalamus?
|
visual pathway to primary cortex
|
|
|
What is found in the occulomotor nucleus?
|
innervation of extraocular muscles except for lateral rectus and superior oblique; also keeps the eyelid elevated
|
|
|
Rubrospinal tract causes flexion or extension of upper extremities?
|
flexion
|
|
|
What are the normal conditions of the rubrospinal tract?
|
normally inhibited by the cortex; otherwise you would have flexion of the UE all the time
|
|
|
What happens if you damage the red nucleus?
|
you have flexion
|
|
|
What are the three cerebellar arteries?
|
SCA, AICA, PICA
|
|
|
What blood vessel is located at the pontomedullary jx?
|
single basilar artery
|
|
|
What blood vessel is located at the pontomesencephalic jx?
|
paired posterior cerebral arteries
|
|
|
What blood vessel supplies the anterior circulation?
|
paired posterior communicating arteries
|
|
|
What is the vascular territory for the superior cerebellar artery (SCA)?
|
arises from top of the basillar artery at level of the rostral pons; supplies superior cerebellum and bit of rostral laterodorsal pons
|
|
|
What is the vascular territory for the anterior inferior cerebellar artery (AICA)?
|
arises from basilar artery (just after vertebrals fuse) at level of caudal pons; supplies lateral caudal pons and small portion of cerebellum
|
|
|
What is the vascular territory for the posterior inferior cerebellar artery?
|
arises from vertebral artery at level of medulla; supplies lateral medulla and inferior cerebellum
|
|
|
What is the blood supply to the midbrain?
|
PCA and penetrating branches "top of the basilar artery"
|
|
|
What is the blood supply to the pons?
|
basilar artery
|
|
|
What is the blood supply to the medial medulla?
|
basilar artery
|
|
|
What is the blood supply to the lateral medulla?
|
vertebral artery and PICA
|
|
|
Infarctions of the brain stem can occur for a number of reasons including?
|
embolism, thrombosis, and lacunar disease
|
|
|
What is lacunar disease?
|
small vessel occlusion in the setting of chronic hypertension
|
|
|
If CN3 and CN4 were affected where in the brain stem would the lesion be?
|
midbrain
|
|
|
If CNs 5,6,7,8 were affected where in the brain stem would the lesion be?
|
pons
|
|
|
If CNs 9,10,12 were affected where in the brain stem would the lesion be?
|
medulla
|
|
|
If CN3 was damaged what would you see in your patient?
|
eye would be down and out, ptosis of eyelid, dilated pupil
|
|
|
If CN7 affected what would you see in pt?
|
Bell's palsy
|
|
|
If CN8 affected what would you see in pt?
|
loss of hearing
|
|
|
If CN12 affected what would you see in pt?
|
problems with the tongue
|
|
|
Lesion to PNS of CN3 causes?
|
dilated pupil and eyeball that is down and out at rest
|
|
|
If there is an SNS problem of CN3 what do you see in pt?
|
Horner's syndrome with pinpoint pupil and eyeball looking straight at you
|
|
|
Which trigeminal nucleus is responsible for the jaw-jerk reflex?
|
mesencephalic trigeminal nucleus
|
|
|
Is cerebral peduncle motor or sensory?
|
motor
|
|
|
Lesions of the brain stem to any of the long tracts will result in what type of body deficit? What are the long tracts?
|
contralateral deficit; corticospinal, spinothalamic, medial lemniscus
|
|
|
Lesion to the descending sympathetic hypothalamic fibers ALWAYS results in?
|
ipsilateral Horner's syndrome on the side of the lesion in the brain stem
|
|
|
Lesion to the cerebellar peduncle will result in?
|
ipsilateral motor ataxia
|
|
|
Damage to CNs and nuclei will result in?
|
ipsilateral head sensory and/or motor deficits
|
|
|
Upper midbrain damage signs of dysfunction?
|
impaired consciousness, flexor posturing, CN3 palsy, unilateral or bilateral pupil dilation, ataxia
|
|
|
Lesion above the red nucleus causes?
|
flexor posturing
|
|
|
Flexor posturing is also known as?
|
decorticate
|
|
|
Upper pontine damage signs of dysfunction are?
|
impaired consciousness, extensor posturing, irregular and apneustic respiration, abducens palsy or horizontal gaze palsy, bilateral small but reactive pupils
|
|
|
Lesion below the red nucleus results in?
|
extensor posturing
|
|
|
Extensor posturing also known as?
|
decerebrate
|
|
|
Horizontal gaze palsy is caused by damage to? How do you name the palsy?
|
PPRF; named for the side that the pt can't look towards
|
|
|
Which area of brain stem damage has a better prognosis?
|
upper midbrain damage
|
|
|
Which area of the brain stem has a worse prognosis?
|
upper pontine damage
|
|
|
Signs of dysfunction in the medulla are?
|
respiratory arrest, vertigo, nausea, ataxia, vomiting, autonomic instability, hiccups
|
|
|
Do medulla lesions have a good prognosis?
|
NO
|
|
|
Lateral medullary syndrome also known as? Caused by?
|
Wallenburg Syndrome; PICA infarct
|
|
|
What is involved in Wallenburg syndrome?
|
lateral tegmentum, not too much motor affected, prognosis is good
|
|
|
Damage to inferior cerebellar peduncles causes?
|
ipsilateral ataxia
|
|
|
Damage to vestibular nuclei causes?
|
vertigo, nausea, nystagmus
|
|
|
Damage to CN5 nucleus and tract causes?
|
ipsilateral facial loss of pain and temperature sensation
|
|
|
Damage to nucleus ambiguus causes?
|
hoarseness and dysphagia
|
|
|
Damage to nucleus solitarius causes?
|
ipsilateral decreased taste
|
|
|
Damage to descending SNS tract causes?
|
ipsilateral Horner's syndrome
|
|
|
Damage to spinothalamic tract (ALS system) causes?
|
contralateral body decreased pain and temperature sensation
|
|
|
A lesion in the medial pontine base is caused by? Also called what?
|
lacunar disease; ataxic hemiparesis
|
|
|
What side is the ataxia on with a medial pontine base lesion?
|
ataxia is same side as the weakness
|
|
|
Vascular supply to the para-median pontine base is?
|
paramedian branches of the basilar artery, ventral territory
|
|
|
If the corticospinal tract is damaged, what are the clincal features?
|
UMN; contralateral leg and arm weakness
|
|
|
If the corticobulbar tract is damaged, what are the clincal features?
|
contralateral face weakness with dysarthria
|
|
|
If the corticobulbar tract is damaged, can the pt close their eye on the affected side?
|
yes, but not as tight as the eye on the unaffected side
|
|
|
Is corticobulbar tract an UMN or LMN?
|
UMN
|
|
|
If the abducens nerve is damaged, what are the clinical signs?
|
ipsilateral paralysis of lateral rectus
|
|
|
If the pontine nuclei and pontocerebellar tract are damaged, what are the clinical signs?
|
contralateral ataxia
|
|
|
Pontocerebellar tract fibers are called?
|
mossy fibers
|
|
|
Which cerebellar peduncle is the major input to the cerebellum?
|
middle cerebellar peduncle
|
|
|
What's found in the middle cerebellar peduncle?
|
pontocerebellar axons
|
|
|
Lesions in the midbrain are caused by infarcts in the?
|
PCA and the vessels from the top of the basilar artery
|
|
|
What is lesioned in oculomotor nerve palsy? Is damage above or below the nucleus?
|
CN3; damage below nucleus
|
|
|
What are the clincal symptoms with oculomotor nerve palsy
|
deviation of eye down and out, drooping of eyelid, dilated nonresponsive pupil
|
|
|
If lesion is at level of midbrain and cerebral peduncle, what are the clincal symptoms?
|
oculomotor nerve palsy and contralateral UMN paralysis
|
|
|
What is the major output of the cerebellum? Where is this output traveling to?
|
superior cerebellar peduncle; thalamus
|
|
|
What is the folia of the cerebellum?
|
cortex; three layers
|
|
|
Where is the cerebellum located?
|
dorsal to midbrain and pons
|
|
|
What is the main function of the cerebellum?
|
regulates movement and posture indirectly by adjusting the output of the major descending motor systems
|
|
|
How does the cerebellum act as a comparator?
|
by comparing intention with performance and compensates for errors in movement
|
|
|
How does the cerebellum correct movement?
|
corrects ongoing movements when they deviate from intended course and modifies the central program so the next movement can fulfill the intended goal
|
|
|
Cerebellum affects what aspects of movements?
|
rate, range, force, and direction
|
|
|
Lesions to the cerebellum cause?
|
ataxia
|
|
|
What is ataxia?
|
uncoordinated and disorganized movements
|
|
|
What three things is the cerebellum not required for?
|
sensory perception, movement of muscles, development of muscle strength
|
|
|
How many hemispheres does the cerebellum have and what divides them?
|
2; midline vermis
|
|
|
What is the function of the primary fissure in the cerebellum?
|
divides it into anterior and posterior lobes
|
|
|
What is the roof of the 4th ventricle?
|
cerebellum
|
|
|
What deep cerebellar nucleus is found in the cerebrocerebellum?
|
dentate
|
|
|
What is the significance of the pineal gland?
|
calcifies with age and can be used as a landmark on XRAY or CT
|
|
|
How does a tumor on the pineal gland affect the patient?
|
Patient won't be able to look up
|
|
|
What are the two components of the spinocerebellum?
|
vermis and paramedian
|
|
|
What divides the posterior lobe from the flocculonodular lobe?
|
posterolateral lobe
|
|
|
The flocculus and nodulus help control? Are in close connection with?
|
balance and eye movement; vestibular system
|
|
|
What can cause the tonsils to herniate through the foramen magnum?
|
increased intracranial pressure, brain swelling, mass lesions of the cerebrum or cerebellum
|
|
|
What is the function of the cerebrocerebellum?
|
complex motor planning; influences planning for the corticospinal system
|
|
|
What is the function of the paramedian part of the spinocerebellum?
|
influences lateral motor tracts and distal limb coordination
|
|
|
What is the function of the vermis part of the spinocerebellum?
|
influences the medial motor tract and proximal limb and trunk coordination
|
|
|
What is the function of the vestibulocerebellum or flocculonodular lobe?
|
balance, posture, and VOR
|
|
|
All of the output of the cerebellar cortex is transmitted by?
|
purkinje cells to the deep cerebellar nuclei
|
|
|
Axons from the purkinje cells form what type of synapses with the deep cerebellar nuclei and vestibular nuclei?
|
inhibitory
|
|
|
Incoming cerebellar inputs via mossy and climbing fibers are ______ to the deep cerebellar nuclei?
|
excitatory
|
|
|
All output from the cerebellum is from the?
|
deep cerebellar nuclei or "roof nuclei"
|
|
|
Lateral to medial what are the names of the deep cerebellar nuclei?
|
dentate, emboliform, globose, fastigial
|
|
|
What is the largest deep cerebellar nuclei? Where does it receive input from? What is it involved with?
|
dentate, cerebrocerebellum, motor planning; active just prior to voluntary movement
|
|
|
What are the interposed deep cerebellar nuclei?
|
emboliform and globose
|
|
|
Where do the interposed nuclei receive input from? What type of movement are they involved with? When are they active?
|
spinocerebellum, movement of appendages, active during and in relation to voluntary movement
|
|
|
Where does the fastigial deep cerebellar nuceli receive input from? What type of movement is this nucleus involved with?
|
spinocerebellum (vermis section) and vestibulocerebellum; trunk coordination and proximal limb movement
|
|
|
What other nucleus functions as a deep cerebellar nuclei?
|
vestibular nuclei
|
|
|
Where does the vestibular nuclei receive input from? What is this nuclei involved with?
|
direct from the vestibulocerebellum; balance and VOR
|
