Audition Lec25

Question 1

what are the 3 divisions of the cochlear nuclei

Answer 1

the dorsal, posteroventral and anteroventral nuclei.

Question 2

the whole range of ____ transduced by the cochlea is represented in each of its three nuclei.

Answer 2

frequencies

Question 3

one ___ = a sine wave

Answer 3

tone

Question 4

oval window is smaller than tympanic
membrane –>

Answer 4

20x pressure increase

Question 5

lever action of ossicular chain –>
___x force increase

Answer 5

1.3

Question 6

• from base to apex there is an increase in

Answer 6

width by a factor of 10

Question 7

• from base to apex there is a decrease in

Answer 7

1. stiffness
2. frequency
3. conduction velocity

Question 8

how are hair cells at the apex compared to the base?

Answer 8

LESS stiff and LONGER

Question 9

High frequency = higher amplitude = ___ distance traveled

Answer 9

shorter

Question 10

___ frequencies go farthest on the basilar membrane

Answer 10

Low

Question 11

Auditory receptor cells at each point along the basilar membrane respond to the amplitude of the traveling wave that ___

Answer 11

reaches it.

Question 12

Hair cells spontaneously oscillate & are most sensitive to sound frequencies which

Answer 12

match their oscillation frequencies

Question 13

The ___ membrane is connected to the basilar membrane via the rigid limbus

Answer 13

tectorial

Question 14

Pushing up the basilar and tectorial membranes shears the cilia in one direction, which opens __channels and depolarizes the cell

Answer 14

K

Question 15

what is the normal potential difference between the sacla media and hair cell interior

Answer 15

150 mV

(scala media = 80 mV, hair cell interior = -70 mV)

Question 16

what pushes K+ into hair cells?

Answer 16

The scala media’s high (+) potential electrochemical gradient (150 mv)

Question 17

what range of frequencies does the 3 cochlear nuclei receive?

Answer 17

each nucleus receives the full
range of frequencies

Question 18

what type of pitch does the auditory cortex receive?

Answer 18

pitch patterns but necessarily pitch

Question 19

Cochlear prostheses bypass the hair cells and excite the___

Answer 19

appropriate nerve fibers.

Question 21

general method of cohclear implants is to pass multiple electrodes into the ___

Answer 21

Scala Tympani.

Question 23

The auditory system respond to a series of rapid fluctuations in______ brought about by the rarefaction and compression of air molecules.

Answer 23

air pressure

Question 25

the greater the magnitude of the amplitude of the sound the greater the

Answer 25

physical magnitude of the sound.

Question 28

how much of the incident energy is transmitted at the oval window

Answer 28

1/1000

Question 30

in decibals how much sound is lost by the time it reaches the oval window

Answer 30

30db

Question 32

At the oval window, only about 1/1000 of the incident energy is transmitted. To compensate for this loss requires an approximately ___ increase in pressure

Answer 32

32-fold

Question 34

The 32-fold increase is accomplished in the ___ ear,

Answer 34

middle

Question 36

The effective area of the tympanic membrane is about 60 square millimeters and that of the oval window about 3 square millimeters. This results in a \_\_\_-fold increase in pressure at the oval window.

Answer 36

20

Question 38

he force at the oval window is not equal to the force applied at the tympanic membrane but actually exceeds it by a factor of

Answer 38

1.3.

Question 40

As a result of forced applied at 1. the oval window 2. at the tympanic membrane the pressure at the oval window is increased by a factor of \_\_\_

Answer 40

26.

Question 42

with tympanometry In **_conductive hearing_** losses more sound is ____ then in the normal middle ear.

Answer 42

reflected

Question 44

Pathologies that result in conductive losses:

Answer 44

1. otitis media 2. otoschlerosis 3. ear wax build up

Question 46

the basilar membrane ___ in width as it runs from the base to the apex of the cochlea.

Answer 46

increases

Question 49

For equally applied forces along the membrane regions of **lower stiffness** will be displaced to a _____ degree.

Answer 49

greater

Question 51

The decreasing stiffness from base to apex results in an increase in\_\_\_ from base to apex.

Answer 51

phase lag

Question 53

As the stapes moves into the oval window a volume of the\_\_\_\_is compressed.

Answer 53

Scala Vestibuli

Question 55

the body compensates for the compression of the Scala Vestibuli by

Answer 55

bulging out of the round window.

Question 57

downward bulge of round window is reet to a neutral position by the resotrative force provided by the

Answer 57

stiff base

Question 61

the greater the frequency of the sound wave, the less the distance the

Answer 61

traveling wave will move along the basilar membrane.

Question 64

The character of the traveling wave, including its points of maximum deflection, is perfectly reflected in the

Answer 64

pattern of discharges transmitted by the primary auditory neurons.

Question 66

It turns out that the peak displacement of the traveling wave is actually very narrow, about the=

Answer 66

width of a few hair cells

Question 68

where is the organ of corti?

Answer 68

the basialr membrane

Question 70

\_\_\_ houses the auditroy receptors

Answer 70

organ of corti

Question 72

Pushing the basilar membrane and the tectorial membrane up will put a ___ action on the cilia in one direction

Answer 72

shearing

Question 74

Electrophysiological recordings have shown that there is a potential difference of +80 millivolts between the ___ and the \_\_\_

Answer 74

scala media and ground.

Question 77

he inside of the hair cell is about ___ millivolts.

Answer 77

-70

Question 79

Hair cells at different points along the basilar membrane differ from one another in their \_\_\_

Answer 79

electromechanical properties.

Question 83

The frequency at which different hair cells oscillate differs according to their \_\_

Answer 83

position along the basilar membrane.

Question 85

\_\_\_\_ is apparent in that each 8th nerve fiber terminates within the cochlear nuclei by branching to each of its three divisions:

Answer 85

Parallelism

Question 86

High frequencies are represented ___ in the nuclei

Answer 86

dorsally

Question 87

Within area AI, neurons of similar best frequency are arrayed

Answer 87

in a strip or belt-like

Question 88

Within area AI, neurons of similar best frequency are arrayed in a strip or belt-like structure that runs perpendicular to the\_\_\_ axis.

Answer 88

high-to-low frequency tonotopic

Question 89

\_\_\_-dimensional spatial organization in the auditory cortex.

Answer 89

three