4.18 Vestibular

Question 1

2 components of vestibular

Answer 1

• peripheral

- central

Question 2

What is in the peripheral vestibular system?

Answer 2

inner ear receptors that signal position and movement of the head

Question 3

The central vestibular system consists of neurons that: (4)

Answer 3

1. contribute to conscious orientation and acceleration through space
2. mediate reflexive adjustments to maintain visual acuity and equilibrium
3. have both sensory and motor function
4. have extensive cerebellar connections

Question 4

Which system depends heavily on vestibular? Why?

Answer 4

• visual

- eyes move in a compensatory way with the head

Question 5

Where do semicircular canals primarily project?

Answer 5

medial and superior vestibular nuclei

not as much to lateral and inferior nuclei

Question 6

semicircular canals are for detection of

Answer 6

rotation

Question 7

What is a major function of the lateral vestibular nucleus?

Answer 7

serves as an important UMN for the lateral vestibulospinal tract

Question 8

What is a major function of the medial vestibular nucleus

Answer 8

important UMN for medial vestibulospinal tract

Question 9

The macula is for

Answer 9

linear acceleration

Question 10

What interacts with the hypothalamus that is important for endocrine autonomics?

Answer 10

RF

Question 11

What does the RF do with respect to vestibular?

Answer 11

controls autonomic responses to vestibular inputs

Question 12

lack of RF input (I think) my cause these vestibular effects

Answer 12

• nausea
• vomiting
• dizziness
• pallor
• sweating

*carsick

Question 13

What are the superior and medial vestibular nuclei for?

Answer 13

eye coordination

Question 14

Which CNs do the superior and medial vestibular nuclei affect? Which reflex is this associated with?

Answer 14

3, 4, 6

VOR

Question 15

components of the bony labyrinth

Answer 15

• 3 semicircular canals
• 2 otolithic organs
• membranous labyrinth

Question 16

How do the semicircular canals detect rotation?

Answer 16

via movement of endolymph

Question 17

position of canals to one another

Answer 17

orthogonal

Question 18

canals open at each end at the

Answer 18

utricle

Question 19

The utrical is an

Answer 19

otolithic organ

Question 20

swelling at the end of the canals

Answer 20

ampulla

Question 21

What does the ampulla contain?

Answer 21

crista

Question 22

What does the crista contain?

Answer 22

• support cells

- hair cells embedded in gelatinous cupula

Question 23

What does the 90˚ orientation of the canals imply?

Answer 23

only 1 set of hair cells affected at a time

Question 24

Hair cells are how this happens

Answer 24

signaling of head acceleration

Question 25

Hair cells are embedded in the

Answer 25

cupula

Question 26

If hair cells bend toward the _____, we get activation

Answer 26

kinocilium

Question 27

If hair cells bend toward the _____, we get inhibition

Answer 27

stereocilia

Question 28

Baseline activity of hair cells

Answer 28

always firing tonically

Question 29

Activation/inhibition causes

Answer 29

speeding up or slowing down of firing rate

Question 30

How do the canals work?

Answer 30

• work in pairs

- get essentially equal and opposite actions

Question 31

What happens when the R side is being activated?

Answer 31

get roughly the same amt of inhibition from the L side

Question 32

What happens to the fluid during spinning?

Answer 32

• fluid speeds up to match rate of turning

- when you stop, the fluid sloshes back

Question 33

With a single plane of rotation, how many pairs of canals are being affected?

Answer 33

ONE