lecture 4 - exam 1

Question 1

parts of the inner ear

Answer 1

cochlea
vestibular system

Question 2

function of the inner ear

Answer 2

provide info to the brain about the body’s position & movement

Question 3

where is the inner ear

Answer 3

temporal bone

Question 4

3 chambers of the cochlea

Answer 4

scala vestibuli
scala media
scala tympani

Question 5

scala vestibuli

Answer 5

filled w perilymph

high sodium ions

Question 6

scala media

Answer 6

holds organ of corti

filled w/ endolymph

high potassium ions

Question 7

scala tympani

Answer 7

filled w/ perilymph

high sodium ions

Question 8

can perilymph & endolymph mix

Answer 8

no

kills hair cells

Question 9

what membrane separates the scala vestibuli & the scala media

Answer 9

Reissners’s membrane

Question 10

what membrane separates the scala media & the scala tympani

Answer 10

basilar membrane

Question 11

organ of corti

Answer 11

sensory organ of hearing

OHCs & IHCs

Question 12

outer hair cells

Answer 12

12000

respond to & modify cochlear travelling wave

electromotile

pass signal to IHC

3 rows?

Question 13

inner hair cell

Answer 13

3500

send signal to auditory nerve

1 row?

Question 14

how does cochlea work

Answer 14

stapes motion causes fluid displacement

creates traveling wave along basilar membrane

Question 15

the traveling wave

Answer 15

energy moves along the cochlea in a traveling wave
- like flicking a jump rope

where it peaks & how far it travels depend on freq of stimulus

Question 16

cochlear tonotopic organization

Answer 16

base = high freqs

apex = low freqs

Question 17

otoacoustic emissions

Answer 17

hair cells are electromotile –> they produce sounds

very low intensity (generally negative dB SPL)

can be measured

Question 18

vestibular system purpose

Answer 18

rapid correction of body’s center of mass to prevent falling

accurate perceptions of body position & direction & speed of movement

control eye movements to maintain a clear visual image

Question 19

semicircular canals

Answer 19

3 canals –> world is in 3D

receptors for angular acceleration or rate of change in angular velocity

tells your brain where your head is

Question 20

utricle & sccule

Answer 20

receptros for rate of change in linear velocity or acceleration

tells your brain if your body is moving in some direction

Question 21

what is the inner ear innervated by

Answer 21

CN VIII - vestibulocochlear nerve

CNVII - facial nerve

Question 22

is AN tonotopic

Answer 22

yes

different AN bundles respond to different characteristic freqs

Question 23

phase locking

Answer 23

ANs tend to fire at the same phase of a signal

for low freqs the AN can fire for every cycle - not possible for high freqs

different AN bundles phase lock to different cycles of the signal

when put together - entire cycle represented

Question 24

how does the AN encode high freqs

Answer 24

AN fibers cannot phase lock to high freqs (>4-5kHz)

encoded by place
tonotopy

Question 25

cochlear nucleus

Answer 25

only ipsilateral connections (same side)

5 cell types that encode different types of auditory info (timing, onset, duration, freq, level)

Question 26

superior olivary complex

Answer 26

where binaural hearing begins
1st place w/ ipsi & contralateral connections

compares input from both sources
ILD & ITD

mediates acoustic/middle ear reflex

Question 27

types of hearing loss

Answer 27

conductive
sensorineural
mixed

Question 28

conductive hearing loss

Answer 28

sound unable to transfer through outer & middle ear

inner ear is intact

air conduction affected, bone conduction not

attenuation of sound pressure
things clear but softer

Question 29

sensorineural hearing loss

Answer 29

cochlea or AN are damaged

outer & middle ear intact

bone conduction affected

sound is quieter & distorted
tinnitus

Question 30

mixed hearing loss

Answer 30

outer/middle ear & inner ear are compromised

air & bone conduction affected