Neuro Vestibular System

Question 1

What are the two components of the otolith organ?

Answer 1

1) utricle
2) saccule

Question 2

The neuroepithelium of the otolith organ is what? What are otoliths?

Answer 2

macula. otoliths are “ear stones” embedded in the macula

Question 3

What is the crista ampullaris?

Answer 3

it is the neuroepithelium of the semicircular canal. Note that the capula “floats” in endolymph

Question 4

The membranous labyrinth is filled with _____, and the membranous labyrinth is suspended with in the ______-filled osseous labyrinth

Answer 4

endolymph

perilymph

Question 5

The ____ labyrinth is sensitive to vibrations from 0-1 Hz

Answer 5

static

Question 6

What else is the static labyrinth sensitive to besides vibrations from 0-1 Hz?

Answer 6

linear acceleration (gravity)

Question 7

What are the otoliths of the static labyrinth embedded in?

Answer 7

the gelatinous macula

Question 8

The dynamic labyrinth consists of ____ pairs of semicircular canals

Answer 8

3

Question 9

The canals of the dynamic labyrinth sense what?

Answer 9

turning movements of the head

Question 10

The dynamic labyrinth is sensitive to vibrations of what hertz?

Answer 10

1-10 Hz

Question 11

What do canals of the dynamic labyrinth respond to?

Answer 11

angular acceleration

Question 12

What is the primary function of the dynamic labyrinth?

Answer 12

provide reflex control of eye movements. When the head turns in one direction, the eyes turn in the opposite direction

Question 13

What part of the semicircular canals detects when the head turns?

Answer 13

The endolymph does not do the detection. The capula of the crista ampullaris detects when the head turns. The afferent fibers fire, signaling that the head is turning

Question 14

When deflected toward the ______, the hair cells of the horizontal semicircular canals increase their firing rate

Answer 14

midline

Question 15

When the head turns, the ____ on one side deflects toward the midline and the hair cell firing rate on that side increases

Answer 15

cupula

Question 16

When the head turns Right, the cupula on the Right deflects ______

Answer 16

medially

Question 17

When the cupula is directed medially, the ____ on the right increases its firing rate

Answer 17

crista ampullaris

Question 18

When the crista ampullaris fires, the eyes respond via the _______ connections to deflect tothe left

Answer 18

vestibulo-ocular

Question 19

The doll’s eye response involves stimulation of _______ and ______ and is seen in young infants and people in coma

Answer 19

semicircular canal and otolith

Question 20

What are the three ascending projections of the vestibular system?

Answer 20

1) medial longitudinal fasciculus
2) pontine tegmentum
3) cerebellum (eye movement control)

Question 21

What is the descending projection of the vestibular system?

Answer 21

spinal cord (control of antigravity muscles)

Question 22

What is nystagmus?

Answer 22

eyes reach the limit of their orbital movement and then suddenly reset to their rest position. The result is an oscillating eye movement. The slow component is vestibular and the fast component is reset

Question 23

What does COWS mean in the context of the caloric test for nystagmus?

Answer 23

COWS - cold, opposite, warm, same

Question 24

Where is the vestibular cortex located?

Answer 24

posterior insular cortex