Auditory Vestibular

Question 1

What is transduction

Answer 1

When physical energy is changed to neural energy

Question 2

Bones of the middle ear

Answer 2

Malleus
Inces
Stapes

Question 3

The 2 rigid connections in the middle ear

Answer 3

Connection between the typanic membrane and the malleus

Connection between the malleus and the incus

Question 4

Flexible connection in the middle ear

Answer 4

Connection between the incus and the stapes

Question 5

What is impedance matching?

Answer 5

When sound reaches fluid in the ear, most of it is reflected back and lost (due to impedence mismatch) so the middle ear bones make up for this and increase sound pressure

Question 6

What is greater - the impedence of air or water?

Answer 6

The impedance of water is much bigger

Question 7

What does Reissner’s membrane separate?

Answer 7

Separates the SV from the SM (scala vestibuli from the scala media)

Question 8

What does the basilar membrane separate?

Answer 8

Separates the SM from the ST (scala media from the scala tympani)

Question 9

Where is the organ of corti and what is it responsible for?

Answer 9

Located in the cochlea at the basilar membrane

Responsible for transduction

Question 10

Effect of sound on the basilar membrane

Answer 10

The width and flexibility of the basilar membrane determines the distance a particular frequency travels

Question 11

What does force TOWARDS the kinocilium do?

Answer 11

Opens TRPA1 channels and K+ enters DEPOLARISING cell

Question 12

What does force AWAY from TRPA1 channels do?

Answer 12

Shuts channels

Question 13

What happens in hair cell transduction?

Answer 13

The tectorial membrane vibrates
The hair cells bend
Depending on how they bend, the hair cells release neurotransmitter
The neurotransmitter released in the hair cell are captured in the nerve fibres
The neural energy is sent to the brain

Question 14

Difference between the inner and outer hair cells?

Answer 14

Inner hair cells are the MAIN source of afferent signal in the auditory nerve

Outer hair cells primarily get EFFERENT inputs. Control stiffness, amplify membrane vibration

Question 15

What do outer hair cells do?

Answer 15

Primary efferent inputs

Control stiffness and amplify membrane vibration

Question 16

What detects head rotation?

Answer 16

The semicircular canals

Question 17

What detects head linear acceleration/translational motion/gravity (and by extension head tilt)

Answer 17

Saccule and utricle

Question 18

What is the crista?

Answer 18

Sheet of cells where hair cells are clustered

Question 19

Orientation of the Kinocili

Answer 19

Orientated in the same direction so all excited or inhibited together

Question 20

What do the otolith organs sense?

Answer 20

Sense linear acceleration and gravity

these are the utricle and saccule

Question 21

What is the vestibulo-ocular reflex

Answer 21

Keeps the eyes still in space when the head turns

Question 22

What is the vestibulo-colic reflex?

Answer 22

Keeps the head still in space - or on a level plane when you walk

Question 23

What is the vestibulo-spinal reflex?

Answer 23

Adjusts posture for rapid changes in position

Question 24

Why can alcohol cause vestibular system dysfunction?

Answer 24

Alcohol is less dense than water so gets into the blood and then into the cupula
The cupula then becomes less dense and floats in the endolymph a bit more
The cupula bends a litter more than usual away from the ground
This bends hair cells as if you are rotating even when you are still

This gives you the sensation of rotating when you are still.

You are drunk.