Vestibular Ocular Reflex (M1) Flashcards Preview

III. Binocular Vision > Vestibular Ocular Reflex (M1) > Flashcards

Flashcards in Vestibular Ocular Reflex (M1) Deck (27):
1

What eye movements account compensate for relatively brief, transient head rotations and translations (walking)?

vestibular eye movements (vestibular ocular reflex, VOR)

2

When the head turns to the right, which horizontal canal is inhibited? 1. What are the yoked ocular muscles that are inhibited? 2

1. left horizontal canal
2. right lateral rectus and left medial rectus

3

What motions do the horizontal canals detect? 1. Does the canal depolarize or hyperpolarize when the head is rotated in the direction of the canal? 2

1. horizontal rotations
2. depolarizes

4

What is the gelatinous body that contains the cilia from the hair cells that make up the crista? 1. What is this responsible for? 2

1. the cupula
2. bows with the flow of endolymph and generates a directional response of the crista (either excitatory or inhibitory)

5

Which ocular muscles are linked to the anterior vertical canals?

1. ipsilateral recti
2. contralateral obliques

6

When the anterior vertical canals are stimulated, what are the yoked muscles that are stimulated?

1. ipsilateral superior rectus
2. contralateral inferior oblique

7

What are the mechanisms of the interaction between the stereocilia and the kinocilium?

1. bending of stereocilia towards kinocilium depolarizes the hair cell, increasing the firing of the nerve fiber
2. bending of stereocilia away from the kinocilium hyperpolarizes the hair cell, decreasing the firing of the nerve fiber

8

How are the semicircular canals arranged relative to each other?

orthogonally (90deg to each other)

9

What are found at the top of the each hair cell that make up the crista within the ampulla?

1. multiple stereo cilia of variable length
2. a single kinocilium at one edge

10

Which vertical canal is inhibited when the head is rotated to the left and then forward (down)? 1. What ocular muscles and inhibited? 2

1. left posterior canal
2. right inferior rectus and left superior oblique

11

Which canals are stimulated when the head is tilted backward (up)? 1. Inhibited? 2

1. posterior canals
2. anterior canals

12

What is the vestibular apparatus adjacent to and continuous with? 1. What is it filled with? 2

1. cochlea in inner ear
2. viscous endolymph

13

For the horizontal canals, is the cupula deflected towards or away from the utricle when it is stimulated?

towards

14

When the head turns to the right, which horizontal canal is stimulated? 1. What are the yoked ocular muscles that are stimulated? 2

1. right horizontal canal
2. right medial rectus and left lateral rectus

15

Which canals are stimulated when the head is tilted forward (down)? 1. Inhibited? 2

1. anterior canals
2. posterior canals

16

Within the ampulla of the semicircular canals, what detects the flow and is a collection of sensory hair cells?

crista (ampularis)

17

For the vertical canals, is the cupula deflected towards or away from the utricle when it is stimulated?

away from

18

What portion of the vestibular apparatus detects linear acceleration (often gravity)?

otolith

19

What portion of the vestibular apparatus detects rotational acceleration?

the 3 semicircular canals

20

What is the latency for rotational VOR? 1. Is this considered fast or slow? 2

1. 16ms
2. very fast

21

When the posterior vertical canals are stimulated, what are the yoked muscles that are stimulated?

1. ipsilateral superior oblique
2. contralateral inferior rectus

22

What is the flow of the endolymph inside of the canals relative to the direction of head rotation? 1. What is it detected by? 2

1. opposite
2. ampulla

23

What are the names of the three semicircular canals?

1. lateral (horizontal)
2. anterior vertical
3. posterior vertical

24

Which ocular muscles are linked to the posterior vertical canals?

1. ipsilateral obliques
2. contralateral recti

25

Which ocular muscles are almost purely vertical acting when the head is rotated to the left?

1. the right recti muscles
2. left obliques

26

Which way do the eyes move relative to the head for VOR movements?

opposite to head movement

27

Which vertical canal is stimulated when the head is rotated to the left and then forward (down)? 1. What ocular muscles and stimulated? 2

1. right anterior canal
2. right superior rectus and left inferior oblique