hearing&vestibular system

Question 1

Explain the movement of the eardrum that allows us to hear

Answer 1

Eardrum moves in and out with the change in air pressure from the sound waves

Question 2

Explain the three dimensions of sound

Answer 2

1. loudness: amplitude
2. pitch: frequency
3. timbre: complexity

Question 3

Name the three ossicles (middle ear bones)

Answer 3

malleus
incus
stapes

Question 4

Describe the pathway through which sound passes through when entering the ear

Answer 4

1. pinna
2. ear canal
3. vibration in tympanic membrane → ossicles (amplifies) → membrane behind oval window
4. cochlea (vibrate fluid)

Question 5

T or F? the basilar membrane encodes low notes on the end of the cochlea closest to the oval window

Answer 5

False, the basilar membrane encodes high notes on the end closest to the oval window

Question 6

Name the three longtudinal divisions of the cochlea

Answer 6

1. scala vestibuli
2. scala media
3. scala tympani

Question 7

People who are completely deaf are missing..

Answer 7

working inner hair cells

Question 8

What is the function of inner hair cells?

Answer 8

Transform sound vibration in the fluids of the cochlea into electrical signal, which are relayed through the auditory nerve to the brain

Question 9

What does the organ of Corti consists of?

Answer 9

basilar membrane (bottom)
tectorial membrane (top)
hair cells (middle)

Question 10

Describe tip links and their functions

Answer 10

elastic filaments that attach the tip of one cilium to another. connected to an ion channel that opens when it’s getting pulled on → glutamate release

Question 11

What happens if tip links break and what does it prevent?

Answer 11

temporary hearing loss: few hours then goes back to normal
prevents excitotoxicity

Question 12

Differentiate place coding from rate coding

Answer 12

place coding: position of hair cell on basilar membrane indicates pitch (high freq)
rate coding: amount of NT released from hair cell (low freq)

Question 13

How is it possible to restore hearing in deaf people?

Answer 13

since they still have axons in auditory nerves, stick metal wires in cochlea → causes action potential = can hear again

Question 14

What may lead you to perceive that the source of a sound is equidistant from your ears?
a. high frequency, from behind
b. low frequency, from the right
c. high frequency, from the left
d. low frequency, from the front

Answer 14

d.

Question 15

Describe the pathway from the ears to the primary auditory cortex

Answer 15

1. info from cochleas → cochlear nerve → cochlear nuclei
2. synapse in superior olivary nuclei and inferior colliculi (sound localization)
3. thalamus → primary auditory cortex

Question 16

In which part of the brain are “where” and “what” info analyzed?

Answer 16

“where”: parietal cortex
“what”: frontal lobe

Question 17

What is the function of the vestibular system?

Answer 17

detects gravity and angular acceleration of the head

Question 18

Explain the role of the 3 semicircular canals in the vestibular system

Answer 18

when we turn, fluid moves and hair cells shift
brain uses it to maintain upright head position, balance, corrects eye movement

Question 19

Explain the role of the utricle & saccule in the vestibular sacs

Answer 19

otoconia in vestibular sac moves with gravity, depolarising the hair cells it sits on