Physiology of the auditory system

Question 1

Define sound

Answer 1

Vibrations that transmit oscillations in pressure over time

Question 2

define amplitude and frequency

Answer 2

Amplitude: size of pressure wave
Frequency: rate of waves per second

Question 3

what is a decibel a unit of?

Answer 3

Decibel: unit of measurement for sound intensity

Question 4

what does an increase in one decibel represent?

Answer 4

A tenfold increase in sound intensity

Question 5

If impulse frequency is high: what happens to the hair cell and what direction do the steriocilia move in?

Answer 5

Excitation (increased impulse frequency): haricots ells are depolarised and shift stereo cilia to the RIGHT (in direction of tall sterocilia)

Question 6

If impulse frequency is LOW: what happens to the hair cell and what direction do the steriocilia move in?

Answer 6

Inhibition (decreased impulse frequency): hyperpolarisation of hair cell, shifts hair cells to the LEFT

Question 7

Compare the loss of inner and outer hair cells

Answer 7

Loss of inner: these convert vibrations into neural signs. So there is unlimited dB loss in hearing = complete hearing loss

Loss of outer: these amplify vibrations. Partial loss in hearing

Question 8

what is place code?

Answer 8

assumption that excitation of a particular place on the basilar membrane gives rise to a specific pitch

Question 9

what is temporal code?

Answer 9

Pitch is coded by the firing rate of nerve impulses in the vestibulocochlear nerve.

Question 10

why does frequency use of NSAIds cause irritation of the gastric mucosa?

Answer 10

Because prostaglandins made by COX1 have a protective role in the gastric mucosa

Question 11

Which part of the eye regulates the amount of light detected by photoreceptor cells?

Answer 11

Iris