Problem 7: The ear

Question 1

what is a sound wave

Answer 1

the movement of vibration changes the pressure in the air, a pattern in air pressure changes is a sound wave

Question 2

from sound wave to ear

Answer 2

vibration in inner ear sets the oval window in motion –> transmits vibration into cochlea –> sets basilar and tectorial membrane into motion –> hair cells are set into motion –> stereo cilia in motion –> bends in one direct –> tip links stretch –> ion channels open –> K+ flows into cell –> cause release of neurotransmitter

Question 3

frequency

Answer 3

the number of cycles per second that the pressure changes repeat

Question 4

amplitude

Answer 4

the size of the pressure changes

Question 5

bekesy theory about frequency etc

Answer 5

the place that vibrates the most depends on the frequency of the tone. he investigated cochleas of cadavers
basilar membrane is the narrowest at the beginning (base) and widens at the apex

Question 6

tonotopic map

Answer 6

map of frequencies along the length of the cochlea

Question 7

auditory masking

Answer 7

ability to hear sound is decreased because there is no other sound present fun

Question 8

auditory canal and its function

Answer 8

protection of middle ear structure, keeping a constant temperature and enhancement of insensitivities
first structure in the ear

Question 9

tympanic membrane

Answer 9

puts the sound into vibration, which goes into the middle ear

Question 10

ossicles + function

Answer 10

• malleus
• incus
• stapes
  they all set each other into vibration, the stapes the transmits it to the oval window
  function: help increase pressure ignorer to transfer the vibration to the inner part of the ear, through a lever action

Question 11

function of the muscles in the middle ear

Answer 11

-contract to dampen the tension in order to protect the middle ear
-prevents very low frequencies from interfering with higher frequencies

Question 12

cochlea

Answer 12

structure that contains the structure that convert sound waves into electricity

Question 13

conductive hearing loss

Answer 13

blockage of sound from reaching the receptors
- otosclerosis (ear bones are not properly formed)
-ear infection (fluid accumulates in middle ear, can’t drain so causes pain and sickness)

Question 14

sensorial hearing loss

Answer 14

damage to the hair cells / auditory nerve or brain
- presbycusis ( caused by the cumulative effects over time of noise exposure, drugs, age, damage to hair cells, high frequencies are affected more)
noise induced hearing loss (loud noises degenerate the hair cells

Question 15

SONIC MG

Answer 15

from cochlear nucleus –> olivary nucleus –> inferior colliculus –> medial geniculate nucleus –> primary auditory cortex

Question 16

superior olivary nucleus

Answer 16

important for locating sounds, signals from left and right ear first meet in this structure