audition

Question 1

why do we have a middle ear?***

Answer 1

to increase the pressure of ear to get the water molecules moving at equal level as the sound changes in the air

Question 2

as the stapes move in due _______ in fluid pressure the basilar membrane bulges _________

Answer 2

increase in fluid pressure, the basilar membrane bulges down

Question 3

high frequency stimulates what part of the cochlea?

Answer 3

the base because it’s the most stiff area

Question 4

low frequency stimulates what part of the cochlea?

Answer 4

the apex and thus it moves from apex to base and moves along the entire basilar membrane

Question 5

the trajectory of sound travel is affected by?

Answer 5

the frequency of the sound NOT the increase in sound pressure

Question 6

for the frequency of a sound on a particular hair cell if the match of frequency is supplied by the stimulus then the displacement required is at a __________ because you give a matching frequency. but if you depart from that matching frequency you must __________ the sound pressure level to cause a just threshold response.

Answer 6

at a minimum

must increase the sound pressure

Question 7

sound is

Answer 7

frequency

Question 8

perception of sound is

Answer 8

pitch

Question 9

change in air pressure is

Answer 9

an auditory stimulus

Question 10

what is the biggest cause of deafness

Answer 10

hair cell death

Question 11

what does the amplitude of a sound wave represent?

Answer 11

the magnitude of pressure change , the greater the amplitude the greater the physical magnitude of sound

Question 12

which part of the ear is filled with an aqueous medium?

Answer 12

the inner ear

Question 13

a 40 dB change means what in terms of the amount that sound must be increased to hear it?

Answer 13

must be increased by 100 fold to hear it and i.e. it is significant hearing loss

Question 14

is the force at the oval window the same as the force applied to the tympanic membrane?

Answer 14

no oval window force exceeds tympanic membrane force by 1.3 x

Question 15

what is tympanometry?

Answer 15

a clinical technique that measures the impedance of he middle ear.

Question 16

what is impedance?

Answer 16

convert low pressure, high displacement vibrations into high pressure of the air into, low displacement vibrations suitable for driving cochlear fluids

the middle ear transfers the incoming vibration from the comparatively large, low impedance tympanic membrane to the much smaller, high impedance oval window.

Question 17

how does tympanometry work?

Answer 17

a microphone is placed in the ear and the amount of sound that is absorbed through the middle ear or is reflected from the middle ear is measured at the microphone

Question 18

what is the normal value in tympanometry? and what could a value above that indicate?

Answer 18

3 dB, > that could indicate wax build up or otitis media ( middle ear infection)

Question 19

bone and soft tissue have an impedance close to ______. therefore w/o a tympanic membrane or middle ear ossicles, sound can be transmitted through bones and soft tissue of the head to the ________

Answer 19

water

cochlea

Question 20

the analysis of different frequencies depends on the way different frequencies affect a membrane in the cochlea called the

Answer 20

basilar membrane

Question 21

there is more deflection at which end of the basilar membrane?

Answer 21

the apex ( think of bending a long stick or a short stick )

Question 22

each frequency of sound has a max deflection and then?

Answer 22

dissipates really quickly in the basilar membrane

Question 23

the character of the traveling of the wave is reflected in the :

Answer 23

pattern of discharges transmitted by the primary auditory neurons

Question 24

auditory receptors arranged in an orderly manner along the basilar membrane are stimulated how and by what?

Answer 24

stimulated mechanically by the displacements of the traveling wave

Question 25

how can you increase the excitation of any auditory nerve fiber by?

Answer 25

presenting a sound wave frequency with a peak traveling wave displacement nearer the position of that fiber’s receptor cell

Question 26

what can you say about the character of the peak displacement traveling wave?

Answer 26

it is very narrow only the width of a few hair cells

Question 27

the organ corti houses the?

Answer 27

auditory receptors

Question 28

the organ corti rests upon the

Answer 28

basilar membrane

Question 29

displacement of the basilar membrane will cause

Answer 29

movement of the auditory cell receptors

Question 30

the basiar membrne operates relative to the what membrane

Answer 30

tectorial membrane

Question 31

pushing the basilar membrane and the tectorial membrane up will

Answer 31

put a shearing force on the cilia in one direction while pushing them down will place a shearing force in the opposite direction

Question 32

what happens when cilia are sheared in a certain direction

Answer 32

the hair cells depolarize and the discharge rate of the neuron increases over it’s spontaneous level.

Question 33

how does the length of the hair cells at the apex compare to that of the those at the base?

Answer 33

the ones at the apex are more than twice as long as the ones at the base.

Question 34

what is the role of the central auditory system?

Answer 34

to interpret the discharge patterns of auditory nerve fibers in order to produce the perception of sound

Question 35

how many cochlear nuclei are there?

Answer 35

3

Question 36

full range of frequencies transduced by the cochlea is represented in each of the 3 nuclei in what manner?

Answer 36

higher frequencies are represented dorsally and low frequencies are represented ventrally in each nucleus

Question 37

in the primary auditory cortex how is the sound organized?

Answer 37

high frequency is more rostral and low frequency is more caudal

Question 38

Is the auditory cortex involved in pitch?

Answer 38

not involved in pitch per se but is involved in the analysis of PATTERNS OF PITCH ( i.e. a series of different frequencies)