Hearing

Question 1

what is pitch

Answer 1

changes in frequency of air over time

Question 2

what is pitch humans perceive

Answer 2

20Hz-20KHz

Question 3

what is loudness in sound

Answer 3

diff between compressed and rarefied air

Question 4

how is loudness measured

Answer 4

in Db - logarhythmic so need 10 fold increase to double

Question 5

what is in the middle ear

Answer 5

air filled space with tympanic cavity and ossicles

Question 6

what do the ossicles span

Answer 6

from tympanic membrane to the oval window of the inner ear

Question 7

what are muscle of ossicle and what innervates them

Answer 7

tensor tympani - V3

stepedius - 7

Question 8

what is point of muscles and what happens if gone

Answer 8

dampen loud sounds - otherwise hyperacusis

Question 9

what is in inner ear

Answer 9

fluid filled space with the vestibule and cochlea

Question 10

what does cochlea spiral around

Answer 10

modiolus

Question 11

what are 3 spaces of cochlea and what are they filled with

Answer 11

scala vestibuli - peripymph
scala vascularis - endolymph
scala tympani - perilymph

Question 12

where is endo lymph from?

Answer 12

stria vascularis - high in K

Question 13

what does the organ of corti rest upon and how does is change along the cochlea

Answer 13

bony spiral lamina - turns to basilar membrane - basilar membrane widens from base to apex

Question 14

how does cochlea change from base to apex

Answer 14

narrows

Question 15

where does sound start and end

Answer 15

begins from foot of stapes in oval window and out the round window on other side

Question 16

what does organ of corti do

Answer 16

turns sound E into receptor potential

Question 17

what is a place code

Answer 17

specific point on the basilar membrane where a specific frequency causes maximal displacement

Question 18

what is covering of organ of corti

Answer 18

tectorial membrane

Question 19

what are 2 types of hair cells and where are they located

Answer 19

outer hair cells - through endolymph into membrane

inner hair cells - into endolymph, but not membrane

Question 20

how are hair cells orders

Answer 20

by hieght, with shortest closest to modiolus

Question 21

what happens with basilar membrane moves up or down

Answer 21

up - hairs cells move inwardsm so stereocilia move out

down - hair cells move out, so hairs move in

Question 22

what does bending cause

Answer 22

receptor potential

Question 23

what happens in bending of 2 directions

Answer 23

towards tallest - depol

towards shortest - hyperpol

Question 24

how does depol happen

Answer 24

movement causes opening of K channels> K in> depol> Ca enters> neurotransmitter released

Question 25

what is ratio of OHC to IHCs

Answer 25

3:1

Question 26

where is most ganglionic input from

Answer 26

95% from IHC

Question 27

what do OHCs do?

Answer 27

amplify mvmt of the basilar membrane to increase low intensity sounds

Question 28

what is path of auditory conduction

Answer 28

coch nerve>ipsi coch nuclei>bilateral projection to inf. coll.> medial geniculate nucleus of thalamus

Question 29

how can unilateral deafness occur (3)

Answer 29

damage to the

1. ear
2. cochlear nerve
3. cochlear nuc.