Hearing Flashcards
Synthesizers make…
pure tones
Instruments and voices make…
sound
What is noise?
indistinguishable sound waves
Functions of the middle ear?
transmission of sound
protection
How much of the sound energy is transmitted via the middle ear ossicles?
60%
How much sound would be transmitted through the air in the middle ear without the ossicles being present?
Only 2% of the sound energy
How does the middle ear help protect hearing?
The onset of a loud sound (60-80dB) induces a contraction of the middle ear muscles with a delay of 50-100ms
How do the muscle contractions help in protecting hearing?
Reduces transmission of low frequencies
Where does the malleus attach?
- To the incus
- To the innermost surface of the tympanic membrane
Where is the foot plate of the stapes located?
In the oval window
Describe the basilar membrane in the cochlea.
At the base, the b.m. is narrow and stiff.
At the apex, the b.m. is wide and floppy.
Where are higher frequencies processed?
Toward the base of the basilar membrane
Where are lower frequencies processed?
Toward the apex of the basilar membrane
Inner hair cells
- true sensory cells
- stimulation alters the rate of release of neurotransmitter gluatamate
- There is one row of inner hair cells
Type I spiral ganglion cells
- sensory neurons
- send one dendrite to an inner hair cel and one axon to the cochlear nucleus
