audition Flashcards
why do we have a middle ear?***
to increase the pressure of ear to get the water molecules moving at equal level as the sound changes in the air
as the stapes move in due _______ in fluid pressure the basilar membrane bulges _________
increase in fluid pressure, the basilar membrane bulges down
high frequency stimulates what part of the cochlea?
the base because it’s the most stiff area
low frequency stimulates what part of the cochlea?
the apex and thus it moves from apex to base and moves along the entire basilar membrane
the trajectory of sound travel is affected by?
the frequency of the sound NOT the increase in sound pressure
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.
at a minimum
must increase the sound pressure
sound is
frequency
perception of sound is
pitch
change in air pressure is
an auditory stimulus
what is the biggest cause of deafness
hair cell death
what does the amplitude of a sound wave represent?
the magnitude of pressure change , the greater the amplitude the greater the physical magnitude of sound
which part of the ear is filled with an aqueous medium?
the inner ear
a 40 dB change means what in terms of the amount that sound must be increased to hear it?
must be increased by 100 fold to hear it and i.e. it is significant hearing loss
is the force at the oval window the same as the force applied to the tympanic membrane?
no oval window force exceeds tympanic membrane force by 1.3 x
what is tympanometry?
a clinical technique that measures the impedance of he middle ear.
what is impedance?
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.
how does tympanometry work?
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
what is the normal value in tympanometry? and what could a value above that indicate?
3 dB, > that could indicate wax build up or otitis media ( middle ear infection)
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 ________
water
cochlea
the analysis of different frequencies depends on the way different frequencies affect a membrane in the cochlea called the
basilar membrane
there is more deflection at which end of the basilar membrane?
the apex ( think of bending a long stick or a short stick )
each frequency of sound has a max deflection and then?
dissipates really quickly in the basilar membrane
the character of the traveling of the wave is reflected in the :
pattern of discharges transmitted by the primary auditory neurons
auditory receptors arranged in an orderly manner along the basilar membrane are stimulated how and by what?
stimulated mechanically by the displacements of the traveling wave
