Vestibular Function Lec28

Question 1

Vestibulo-Ocular Reflex - maintains

Answer 1

steady gaze

Question 2

Vestibulo-Ocular Reflex moves the eyes

Answer 2

opposite to head so they stay fixed on a point

Question 3

Vestibulo-Colic Reflex - maintains

Answer 3

orientation of head and neck against gravity

Question 4

Vestibulo-Spinal Reflex isn involved in ___ and ___

Answer 4

kinesthetic awareness, correction for stumbling.

Question 5

The Vestibular System can detect (3)

Answer 5

rotation, translation, and gravity

Question 6

The 3 semicircular canals sense

Answer 6

rotational movement/angular acceleration

Question 7

The otoliths (utricle and saccule) detect ___-

Answer 7

translational movement/linear acceleration & gravity

Question 8

where are hair cells found in the vestibular system

Answer 8

in 3 semiciruclar canals, otoliths

Question 9

Utricle is oriented to sense ___ acceleration,

Answer 9

horizontal

Question 10

Sacculus is oriented to sense ___ acceleration

Answer 10

vertical

Question 11

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

Answer 11

“otolithic membrane”

Question 12

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

Answer 12

opposite direction

Question 13

if hair bends towards kinocilia then __ occurs

Answer 13

cn 8 excitement, depolarization

Question 14

if hair bends away from kinocilia then

Answer 14

hyperpolarization, cn 8 inhibitor

Question 15

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

Answer 15

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

Question 16

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

Answer 16

ampulla

Question 17

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

Answer 17

sterocilia in the paired canal

Question 18

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

Answer 18

cupula

Question 19

____ displaces endolymph –> which displaces the cupula.

Answer 19

Acceleration

Question 20

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

Answer 20

excites

Question 21

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

Answer 21

inhbiits

Question 22

VOR Rotation to the L. excites the

Answer 22

L. CN 8 & L. vestibular nuclei,

Question 23

VOR The L. vestibular nuclei excite the ____

Answer 23

R. abduscens and left medial rectus

Question 24

VOR L. vestibualr n. excites abduscens —> activates

Answer 24

right lateral rectus muscle

Question 25

increased firing in one canal means the head is

Answer 25

rotating toward that side

Question 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

Answer 26

the side

Question 27

he vestibular system is poor at detecting constant ___

Answer 27

velocity motion.