Lecture 35 - Vestibular system

Question 0

What is the task of the auditory system?

Answer 0

Transduce vibration into electrical activity

Question 1

What are the tasks of the vestibular system?

Answer 1

Senses head movements
Maintain visual axes when head is moving
Send motor commands to trunk and limb muscles to maintain balance

Question 2

What are three sections of the membranous labyrinth?

Answer 2

Utricle - Saccule - Semicircular ducts

Question 3

What is the function of the utricles?

Answer 3

Monitor and activate response to linear acceleration of horizontal movements

Question 4

What is the function of the saccule?

Answer 4

Monitor and activate response to linear acceleration of vertical movements

Question 5

What is the function of the Semicircular ducts?

Answer 5

Monitor and respond to angular acceleration of head in all planes

Question 6

What is the orientation of the semicircular ducts?

Answer 6

Anterior - Lateral - Posterior

Question 7

What neural structure is associated with the vestibular system?

Answer 7

Scarpa’s ganglion - vestibular ganglion

Question 8

What is the electrolyte composition of the perilymph?

Answer 8

Increased Na concentration

Question 9

What is the electrolyte composition of the endolymph?

Answer 9

Increased potassium concentration

Question 10

What are three main structures in an ampulla?

Answer 10

Crista - Cupula - Hair cells

Question 11

What are the three main structures of the hair cells?

Answer 11

Stereocilia - Kinocilium - Afferent/Efferent fibers

Question 12

What fluid are the hair cells sitting in?

Answer 12

Endolymph

Question 13

What happens within the ampulla when the endolymph is moving?

Answer 13

Bends cupula, which in turns tilt the stereocilia and kinocilium

Question 14

What structure contains the ampullas?

Answer 14

Semicircular ducts

Question 15

What structure are the hair cells embedded into?

Answer 15

Crista

Question 16

What are the structures in the otolithic organs?

Answer 16

Otolithic membrane, Otoconia, Macula, Striola

Question 17

What are the two otolithic organs?

Answer 17

Utricle and saccule

Question 18

What is moved with the head is moved within the otolith organs?

Answer 18

Cap of statoconia movies, causing bending of the hair cells

Question 19

What happens in the otolith organs when the sterocilia bend toward the kinocilium?

Answer 19

Hair cells depolarize

Question 20

What molecular structure is linked to the depolarization of the hair cells?

Answer 20

Tip link

Question 21

What does the tip link do?

Answer 21

Opens mechanically gated K+ channels
More voltage gated calcium channels open
Increase glutamate release

Question 22

What happens in the semicircular ducts when the stereocilia are deflected towards kinocilium?

Answer 22

Apical K+ channels open
Depolarization of the cell membrane
Calcium channels open
Synaptic vesicles to open

Question 23

What nerve is affected when the hair cells are depolarized?

Answer 23

Afferent nerve firing is increased

Question 24

What happens when the stereocilia deflected away from kinocilium?

Answer 24

Decreased firing rate

Question 25

What are the four vestibular nuclei?

Answer 25

Superior - Inferior - Medial - Lateral

Question 26

What is VOR?

Answer 26

Vestibular reflex with the function of keeping the eyes on an object when the head is in motion relative to that object

Question 27

How is the VOR carried out?

Answer 27

Contraction of the extra-ocular eye muscles required to keep that image of that object focused on the fovea

Question 28

What happens when there is a lesion on the vestibular portion of the CN VIII, vestibular apparatus, or nuclei?

Answer 28

Perception of moving when not

Question 29

What are the components of the spiral organ?

Answer 29

Outer hair cells Inner hairs Inner hair cell

Question 30

Where is low frequency sound processed?

Answer 30

Towards the helicotrema

Question 31

Where is high frequency sound processed?

Answer 31

Toward the oval window

Question 32

What scala interacts with the oval window?

Answer 32

Vestibuli

Question 33

What scala interacts with the round window?

Answer 33

Tympani

Question 34

What is a sound wave?

Answer 34

Pressure displaces scala vestibuli which displaces cochlear duct and spiral organ

Question 35

What projects into the tectorial membrane?

Answer 35

Stereocilia

Question 36

What nerve goes into the scala tympani?

Answer 36

Cochlear nerve through the spiral ganglion

Question 37

How does a hair cell depolarize?

Answer 37

Hair cells bend towards the kinocilia Opens the mechanically gated potassium channels More Ca2+ voltage gated open Glutamate released

Question 38

What is auditory information delivered to and processed in?

Answer 38

Auditory cortex