Vestibular

Question 1

5 vestibular receptor organs

Answer 1

1. Horizontal SSC
2. Posterior SSC
3. Anterior SSC
4. Sacculus
5. Utricle

Question 2

3 relationships between SCCs and utricle

Answer 2

1. at right angles to each other
2. Anterior SCC is coplanar with contralateral Posterior SCC
3. Horizontal SCC and utricle usually parallel with earth

Question 3

Receptive area of SCC

Answer 3

ampulla

Question 4

The thickened epithelium in the ampula is called

Answer 4

Ampullary crista

Question 5

The ampulla contains

Answer 5

Culupa: gelatinous diaphram + hair cells within

Question 6

What is displaced by endolymph current?

Answer 6

Cupula

Question 7

Hair cells depolarize when they’re bent….

Answer 7

toward the kinocilium

K+ channels open and K+ flows in

Question 8

Hair cells hyperpolarize when they’re bent…

Answer 8

away from the kincilium

Basolateral K+ channels open and K+ flows out

Question 9

Physical relation of SCC kinocilium to utricle

Answer 9

Horizontal: kinocilium closer to utricle

Anterior & Posterior: kincilium on side farther from utricle

Question 10

Horizontal SCC when head turns Left

Answer 10

Left depolarize

RIght hyperpolarize

Question 11

Horzontal SCC when head turns Rights

Answer 11

Right depolarizes

Left hyperpolarize

Question 12

Orientation of otolithic organs

Answer 12

Utricle: horizontal
Saccule: verticle

Question 13

What does the otolithic membrane contain

Answer 13

otoliths/otoconia

macula that contain steriocilia

Question 14

How does the utricle respond to head rotation?

Answer 14

It doesn’t

Question 15

What direction polarizes otolith hair cells? Why?

Answer 15

Many different directions

Because the striola curves through the macula

Question 16

What are the otoliths?

Answer 16

Calcium carbonate-protein granules

They give us info about gravity

Question 17

What does the utricle determine?

Answer 17

Degrees of head tilting

Question 18

What does the utricle determine?

Answer 18

Up and down/verticle movements of head

Question 19

3 types of vestibulo-ocular reflexes and input and functions

Answer 19

Rotational:compensates for head rotation, from SCCs (yaw)
Translational: linear movement/pitch, Otoliths
Ocular Counter-Rolling: head tilt/roll, Otoliths

Question 20

How do vestibular hair cells depolarize

Answer 20

Stereocilia toward kinocilium:
K in from endolymph
Ca flows in
After, K out into perilymph

Question 21

How do vestibular hair cell hyperpolarize?

Answer 21

Sterocilia away from kincilium:
Basolateral K channels open
K flows out

Question 22

3 limitations of vestibular system

Answer 22

1. Not a perfect transducer of head mvmt
2. Habituates
3. Canals do not respond well to slow head movement

Question 23

What assists vestibular system in limitation

Answer 23

The optokinetic system

Question 24

What is the site of processing positional and movement info?

Answer 24

The 4 vestibular nuclei

Question 25

SCCs project primarily to?

Answer 25

superior and medial vestibular nuclei

Question 26

Cerebellar afferents to VN: NT? Controls?

Answer 26

GABA

Eye and head movement, posture

Question 27

What provides proprioceptive input?

Answer 27

Spinovesitbular fibers

Question 28

Inputs from where mediate info about head mvmt and vision?

Answer 28

Accessory optic system

Question 29

Vestibulospinal reflexes do

Answer 29

reflexive postural adjustments of head and body

Question 30

Lateral vestibulospinal tract:
From
Path
For

Answer 30

Lateral vestibular nucleus
Uncrossed and runs length of spine
Enables vestibular apparatus to influence ipsilateral prosimal limb muscles