Vestibular Function Lec28 Flashcards Preview

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Flashcards in Vestibular Function Lec28 Deck (27):
1

Vestibulo-Ocular Reflex - maintains

steady gaze

2

Vestibulo-Ocular Reflex moves the eyes

opposite to head so they stay fixed on a point

3

Vestibulo-Colic Reflex - maintains

orientation of head and neck against gravity

4

Vestibulo-Spinal Reflex isn involved in ___ and ___

kinesthetic awareness, correction for stumbling.

5

The Vestibular System can detect (3)

rotation, translation, and gravity

6

The 3 semicircular canals sense

rotational movement/angular acceleration

7

The otoliths (utricle and saccule) detect ___-

translational movement/linear acceleration & gravity

8

where are hair cells found in the vestibular system

in 3 semiciruclar canals, otoliths

9

Utricle is oriented to sense  ___ acceleration,

horizontal

10

Sacculus is oriented  to sense ___ acceleration

vertical

11

The utricle and sacculus hair cells project into a gelatinous ___ with otoconia, calcium carbonate crystals which provide mass

“otolithic membrane”

12

Inertial forces on the head will displace the otolithic membrane and hair cells in the ___ direction

opposite direction

13

if hair bends towards kinocilia then __ occurs

cn 8 excitement, depolarization

14

if hair bends away from kinocilia then

hyperpolarization, cn 8 inhibitor

15

he 3 pairs of semicircular canals on each side of the head work

together Rotation in a particular direction will excite the hair cells of one canal and inhibit the hair cells in its partner.

16

All the hair cells in a canal’s ___ are oriented in the same direction

ampulla

17

All the hair cells in a canal’s are opposite of the ____

sterocilia in the paired canal

18

The ampulla of each canal has a gelatinous membrane called the ___

cupula

19

____ displaces endolymph --> which displaces the cupula.

Acceleration

20

Head rotation to face R. ____ the R. horizontal canal

excites

21

Head rotation to face R. excites the L. horizontal canal

inhbiits

22

VOR Rotation to the L. excites the

L. CN 8 & L. vestibular nuclei,

23

VOR The L. vestibular nuclei excite the ____

R. abduscens and left medial rectus

24

VOR L. vestibualr n. excites abduscens ---> activates

right lateral rectus muscle

25

increased firing in one canal means the head is

rotating toward that side

26

Vestibular balance nystagmus – one side has less firing than the other, so the other side compensates

 

eyes move slowly to ___ of the decrease firing and then back to midlin

the side

27

he vestibular system is poor at detecting constant ___

velocity motion.