Lecture 10, Vestibular

Question 1

Roles of Vestibular System

Answer 1

Perception
BP control
Descending control of proximal and axial muscles
eye movement control

Question 2

Vestibular ganglion of Scarpa

Answer 2

contains cell bodies of primary sensory neurons for vestibular organ

Question 3

Utricle and saccule

Answer 3

recognizes backward movements

Question 4

Otoliths

Answer 4

recognizes displacement of head, within macula

Question 5

Semicircular Canals

Answer 5

movement of head causes movement of endolymph through the ampullae

rotation of head is interpreted by the canals, the cupula (hair cells) are embedded. Hair cells will activate primary sensory neurons, which send info to the vestibular nerve

Question 6

Utricle detects….

Answer 6

horizontal movements

Question 7

Saccule detects….

Answer 7

vertical movement

Question 8

Superior vestibular ganglion

Answer 8

receives input from utricle, anterior saccule, and semicircular canals

Question 9

Inferior vestibular ganglion

Answer 9

receives input from the posterior saccule and post semicircular canals

Question 10

Angular motions….

Answer 10

are controlled by semicircular canalsonitored

Question 11

Linear motions

Answer 11

are monitored by urtricle and saccule

Question 12

Lateral vestibular nucleus

Answer 12

gives rise to the lateral vestibulospinal tract
part of medial descending motor system
helps to maintain balance and extensor tone

Question 13

Medial Vestibular Nucleus

Answer 13

largest of vestibular nuclie
give rise to medial vestibulospinal tract
medial descending motor system
only extends cervical spine
important in controlling head and neck position

Question 14

Medial longitudinal fasciculus

Answer 14

medial vestibular nucleus and superior vestibular nucelus send fibers to ascend in MLF to the oculomotor, trochlear, and abducens nuclei

pathway controls vestibulo-ocular reflex

Question 15

VOR

Answer 15

stabilizes the eys of the visual image
inputs from nuclei travel in MLF to control extraocular nuclei

Question 16

Dizziness

Answer 16

vague term used by patients to describe many different abnormal sensations

Question 17

Vertigo

Answer 17

spinning sensation of movement
more indicative of vestibular disease
can be caused by lesions anyway in pathway
most cases are caused by inner ear

central = brainstem or cerebellum, less common

Question 18

BPPV

Answer 18

positional vertigo
otoconia from otoliths can become dislodged and moved into semicircular canals
causes increased sensitivity to head movement

can be treated with maneuvers