Auditory Flashcards
(19 cards)
What’s the human audible spectrum?
20Hz to 20kHz
What’s the function of the external ear?
Gather and focus sound energy
What’s a property of the pinna and concha?
Provide cues about elevation and sound source
Why is it necessary to boost the signal from outer to inner ear?
Because the fluid of the cochlea has a higher impedance than air (more resistant to mvt)
What two processes boost pressure in the middle ear?
- large surface area to small surface area
- lever action of the ossicles
What’s the purpose of the tensor tympani and stapedius?
Regulate the efficiency of sound transmission (if too loud, contract)
True or False? The scala vestibuli and scala timpani are always separated in the cochlea
False. They merge at the helicotrema
What makes the cochlea sensitive to varying frequencies?
The varying stiffness of the basilar membrane
Why is the receptor potential of inner hair cells biphasic?
The back and forth movement creates a graded receptor potential (ups and downs are defined)
What’s the advantage of mechanical gating for inner hair cells?
Fast and sensitive response
Is damage to stereocilia reversible?
No
Is damage to tip-links reversible?
Yes (within few hours)
What’s the difference between high and low frequencies when it comes to receptor potentials?
<3kHz, displacement follows frequency
if over, simply tracks amplitude
What’s an advantage of the different extracellular environments of inner hair cells?
supports fast and efficient repolarization
ensures ionic gradient during prolonged stimulation
What’s an advantage of tonotopic organization of the basilar membrane?
labeled-line coding
each nerve linked with specific frequency
What’s the characteristic frequency of a nerve fiber?
weakest sound stimulus that it responds to
What are all sound location systems?
Vertical: pinna + concha
Horizontal: ITD + IID
What do ITDs not work for stimuli above 3kHz?
Can’t differentiate between start and end of stimuli (only knows amplitude)
What’s the topography of the auditory cortex?
Based on auditory space (where sound is from) + tonotopic map + EE/EI stripes
