050 Central Auditory processing 1

Question 1

How does the ear reduce area to match impedence?

Answer 1

From tympanic membrane to stapes, it decreases in size from 20:1

Question 2

How does the ear increase force to match impedence

Answer 2

The lever action of the malleus.
The arm of the malleus is also longer than of incus.
Buckling of the ear drum

Question 3

What is the relationship between frequency (w), mass (m) and stiffness (k)

Answer 3

w2 = k/m

Frequency is a function of stiffness / mass. To increase frequency, you must increase stiffness (higher at bass) and lower in mass (less fluid)

Question 4

When do inner hair cells perform AC or DC responses?

Answer 4

AC response occurs at low frequency - hair cell follows every cycle of the stimulus.

DC response occurs at high frequency - hair cell remains depolarised.

Question 5

Which protein do outer membrane hair cells contain and what does it do?

Answer 5

Prestin - change in voltage will change the shape of the outer hair cell, which changes the basilar membrane.