Auditory System

Front 1

What are the parts of the external ear?

Back 1

1) concha
2) pinna
3) auditory meatus
4) tympanic membrane

Front 2

What are the parts of the middle ear?

Back 2

1)ossicles
2) stapedius
3) tensor tympani

Front 3

What is conductive hearing loss?

Back 3

something that interferes with the external ear or middle ear's ability to transfer sound to inner ear

Front 4

What is sensineural hearing loss?

Back 4

inner ear is effected so either cranial nerve 8 or the hair cells themselves

Front 5

What is the cochlear partition made of?

Back 5

tectorial and basilar membrane

Front 6

What is the organ of corti?

Back 6

ribbon of sensory epithelium which runs down cochlea scala media and contains hair cells

Front 7

What do acoustic signals do in the cochlea?

Back 7

they initiate a wave of the same frequency which moves from base to apex of basilar membrane growing in amplitude until the point of maximum displacement and then hair cells respond to that specific freqeuncy

Front 8

What are inner hari cells?

Back 8

main sensory receptors of cochlea that sens vibration of organ of Corti to cochlear nuclei in brain stem

Front 9

What are outer hair cells?

Back 9

target of efferent innervation and possess a unique type of mobility that allows them to be amplifiers

Front 10

What are the characteristics of the base of the cochlea? (3)

Back 10

1)stiff
2) narrow
3) high frequency

Front 11

What are the characteristics of the apex of the cochlea?

Back 11

1)floppy
2) wide
2) low frequncy

Front 12

What happens to the frequency as you get away from teh stapes?

Back 12

freqenucy decreases

Front 13

What happens when you stretch the stereocilia apart from each other?

Back 13

open cation sensitive channels at end of link and depolarize the hair cell

Front 14

What happens when you compress the tip links?

Back 14

close channels and cause hyperpolarization

Front 15

Where are the compartments of the perilymph and endolymph located with relation to the basilar and tectorial membranes?

Back 15

perilymph is outside of the scala media in scala tympani or scala vestibuli it is either over the tectorial membrane or under the basalar membrane

Front 16

What is the relative composition of endolymph to perilymph to hair cell ?

Back 16

endolymph- low K, 0 mV
perilymph - hi K, 80 mV
hair cell: -45mV

Front 17

How do you drive K into hair cell?

Back 17

perilymph is higher in K than hair cell

Front 18

What happens once you depolarize the hair cells?

Back 18

1)open more voltage gated Ca and K channels in hair cell soma
2) K goes from apical end to basilar end
3) Ca coming from voltage gated channel causes NT release to afferent nerve cell

Front 19

What is the central pathway for processing auditory information?

Back 19

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1) hair cell
2) spiral ganglion
3) auditory nerve
4) ventral cochlear nucleus
5) superior olive
6) lateral lemniscus
7) inferior colliculus
8) MGN
9) auditory cortex

Front 20

What is the ratio of hair cell to auditory nerve fiber?

Back 20

1:1 which gives the tuning curve because each hair cell is tuned to a specific frequency so each auditory nerve is tuned to a spcific frequency

Front 21

What is the difference between auditory nerves in apical end vs basilar ends?

Back 21

apical end - low frequency
basilar end - high frequency

Front 22

What is the MSO nucleus for?

Back 22

detecting coincidence when excitatory signals arrive at same time. useful for localizing sound under 3Hz

Front 23

What is used to for localizing sounds above 3Hz?

Back 23

LSO and MNTB

Front 24

What analysis interaural intensity?

Back 24

LSO

Front 25

What does the midbrain do ?

Back 25

merge auditory information

Front 26

What does the lateral lemniscus do?

Back 26

signal onset of sound and duration for monaural

Front 27

What does the inferior colliculus do?

Back 27

auditory space map
process sound with complex temporal pattern

Front 28

What does the auditory thalamus do

Back 28

belt areas and medial areas

Front 29

What is the primaru auditory cortex?

Back 29

superior temporal gyrus which has precise temporal map from MGN

Front 30

What is the secondary auditory cortex?

Back 30

belt areas also known as A1, behind lateral sulcus near Wernicke's area

Front 31

What is the difference between hearing aids and cochlear implant?

Back 31

hearing aids amplify sound
cochlear implant - compensate for damaged or non working parts of ear

Front 32

Can cochlear implants restore normal hearing?

Back 32

no

Front 33

What is the primary auditory cortex essential for?

Back 33

frequency discrimination and sound lcoalization

Front 34

Where is the primary auditory cortex located?

Back 34

superior temporal gyrus

Front 35

What are the structures that hearing implants bypass?

Back 35

1) ear canal
2) tympanic membrane
3) oval window
4) hair cells

Front 36

What do cochlear implants do then?

Back 36

they stimulate auditory nerve directly

Front 37

What is the mechanism of how cochlear implants work?

Back 37

1)perform fourier analysis on sound
2) excite cells to degree that their frequency is active
3) have alot of electrodes
4) number of electrodes they have determines function

Front 38

How is cochlear implant surgery performed?

Back 38

general anesthesia

Front 39

When can the pt be able to hear after the surgery?

Back 39

1 month

Front 40

What are factors that influence performance of cochlear implants on patients?

Back 40

1)age of onset of hearing loss
2)age of implementation
3) duration of cochelar implant

Front 41

What are two ways to test newborn hearing

Back 41

1)ABR (auditory brainstem response testing)
2)OAE (otoacoustic emissions testing)

Front 42

What is the most common birth defect?

Back 42

hearing loss