Vestibular System (Section 4)

Question 0

Semicircular canals are oriented so they can detect what acceleration?

Answer 0

Angular acceleration in three planes (horizontal, anterior, and posterior)
And Direction of head movement

Question 1

The vestibular system provides the nervous system with info that is important in what two areas?

Answer 1

Reflex control of eye movements (vestibulo-ocular reflex)

Reflex control of upright posture (vestibulospinal reflex)

Question 2

Both ends of each semicircular canal terminate where?

Answer 2

Utricle

Question 3

Each semicircular canal has an enlargement called what?

Answer 3

Ampulla

Question 4

What is the cupula

Answer 4

a gelatinous mass surrounding the vestibular hair cells only in the ampulla

Question 5

Fluid in the semicircular canals?

Answer 5

Endolymph

Question 6

What happens to the semicircular canal when the head is moved?

Answer 6

Initially, the fluid in the canal retains its original position because of inertia. The inertia is eventually overcome and moves at the same rates as the rest of the head

Question 7

Hair cells are stimulated only during:

Answer 7

Changes in the rate of motion

Question 8

Bending of the hairs towards the kinocilium causes what?

Answer 8

Depolarization leading to an increase in the firing rate of CN VIII

Question 9

Deflection of hair cells away from kinocilium in opposite direction causes what?

Answer 9

Hyperpolarization and a decreasing firing rate in CN VIII

Question 10

T or F, the brain only receives one indication during turning motion, the indication of depolarization

Answer 10

False! It receives two indications of this turning motion, an increase in the firing on one side and a decrease on the other

Question 11

Otolith organs provide the nervous system with two types of information:

Answer 11

Linear acceleration and head position with respect to gravitational forces

Question 12

What is the role of the Vestibulo-Ocular Reflex

Answer 12

Help maintain a stable visual image on the retina while the head is moving

Question 13

Superior Vestibular nucleus Receives input from:

Answer 13

Ampullae of Semicircular ducts
Maculae of utricle
Cerebellum

Question 14

What two vestibular nuclei join the ascending component of MLF

Answer 14

Superior Vestibular Nucleus

Medial Vestibular Nucleus

Question 15

What two vestibular nuclei are involved in the Vestibulo-ocular reflex

Answer 15

Superior Vestibular Nucleus

Medial Vestibular Nucleus

Question 16

Lateral Vestibular Nucleus receives input from

Answer 16

Utricle

Question 17

Lateral vestibular nucleus gives rise to what tract?

Answer 17

Lateral vestibulospinal tract

Question 18

Lateral vestibular nucleus is involved in what reflex

Answer 18

Vestibulospinal reflex (helps maintain balance & upright posture)

Question 19

Medial Vestibular nucleus gives rise to what tract?

Answer 19

Medial Vestibulospinal tract which eventually joins descending component of MLF

Question 20

Medial Vestibular nucleus receives input from where:

Answer 20

Ampullae of semicircular ducts

Question 21

Inferior Vestibular nucleus contributes some neurons to where?

Answer 21

Vestibulospinal pathways & Cerebellum

Question 22

Inferior Vestibular Nucleus is involved in what control?

Answer 22

Postural control and integrate peripheral input from the vestibular apparatus with input from the cerebellum