Auditory and vestibular system physiology Flashcards Preview

Neurology > Auditory and vestibular system physiology > Flashcards

Flashcards in Auditory and vestibular system physiology Deck (36):
1

What is the organ of hearing?

Hair cell

2

Which neurotransmitter is involved in the auditory system?

Glutamate

3

Which ion is involved in hair cells?

Potassium

4

Which nerve endings will glutamate act on at the hair cell?

Efferent nerve endings

5

Will sound be amplified or reduced in the middle ear?

Amplified to allow it to travel in the fluid of the inner ear

6

What separates the scala vestibuli from the scala media?

Reissner's membrane

7

What separates the scala media from the scala tympani?

Basilar membrane

8

Describe transduction in the corti hair cells?

Basilar membrane to tectorial membrane

9

What connects the scala vestibuli and the scala tympani?

Helicotrema

10

What windows does the sv and st connect with respectively?

SV = oval window
ST = round window

11

Where can perilymph be found?

Scala vestibuli
Scala tympani

12

Where can endolymph be found?

Scala media

13

Describe the rigidity of the basilar membrane from the base to the apex?

Rigid at base
Floppy at apex

14

Where will high and low pitched sound be heard within the cochlea?

High = base
Low = apex

15

Where will the rods of corti synapse?

Bipolar neurones with the cell body in the spiral ganglion

16

Will potassium move inwards or outwards in the organ or corti?

Inwards

17

Describe the components of perilymph and endolymph

Perilymph: high sodium, low potassium, glucose of 4
Endolymph: low sodium, high potassium, glucose of 0.5

18

Mutations in what can result in deafness?

Recycling of K+ in the endolymph

19

What will inner hair cells communicate with?

Main source of afferent signal

20

What is the input to outer hair cells?

Efferent inputs from the superior olivary complex

21

What is the function of outer hair cells?

Stiffness
Amplify membrane vibration

22

What protein is present on outer hair cells?

Prestin which can change the length of the cell

23

How does furosemide act in the middle ear?

Inactivates prestin damaging auditory system

24

What will outer hair cells respond to sound with?

Receptor potential
Change in length - movement of tectorial membrane

25

What does tonotopy ensure?

Each neurone innervates several different areas and different neurone types

26

What is tonotopy?

Spatial arrangement of where sounds of different frequencies are processed within the brain

27

What is the function of the medial superior olive?

Computes sound arrival at the 2 ears to generate an interaural time difference using a delay line

28

What is the function of the vestibular system?

Gaze and postural stability
Sense of orientation
Detection of linear and angular acceleration

29

What part of the vestibular system determines head angular acceleration?

Semicircular canals

30

What part of the vestibular system determines head linear acceleration?

Saccule = vertical
Utricle = horizontal

31

Where can hair cells be found in the semicircular canals?

Crista at the ampulla
They will project into the cupula

32

In semicircular canals are the kinocilium orientated in the same or different direction?

SAME so all excited or inhibited together

33

Are the semicircular canals filled with endolymph or perilymph?

Endolymph

34

Where can otorocnia be found?

Otolithic membrane

35

What is the striola in the macula?

Structural landmark
Arranged otoconia into narrow trenches dividing otolith
This allows otolith organs to have multidirectional sensitivity

36

What are the 3 main vestibular reflexes?

VOR - eyes still in space as head moves
Vestibulo-colic reflex - keeps head still in space when you walk
Vestibular-spinal reflex - adjusts posture for rapid changes in position