crowded together, high
At peaks of the waves, molecules are __, and the pressure is
___.
far apart, low
At the troughs the molecules are ___, and the pressure is ___.
frequency
the number of wave peaks per second
pitch
we perceive frequency as:
low-pitched
we hear low frequencies as:
high-pitched
we hear high frequencies as:
16-20000Hz (10 octaves)
range of human hearing
1000-3000 Hz
human hearing, range of highest acuity
Amplitude
the pressure difference between peak and trough
,loudness
Amplitude is the main factor that determines our perception of
___
frequency
Loudness also depends on ___, no matter how large an
amplitude a sound won't be heard if it is beyond the range of
human hearing.
eardrum
sound waves vibrate the ___
eardrum to malleus to incus to stapes
vibration chain: __ to __ to __ to __
malleus
"hammer" bone, moves the incus
incus
"anvil" bone, moves the stapes
stapes
"stirrup" bone, pushes like a piston agains the oval window
oval window
a membrane between the middle and inner ear, pushed against
by the stapes. Vibration sets up waves in the perilymph
ossicles
,the smallest bones in the body, includes the malleus, incus, and
stapes. Act as a lever system to carry vibrations from the
eardrum to the oval window.
cochlea
a coiled, bony, fluid-filled tube that contains the receptor cells
Vestibular Duct (scala vestibuli)
contains perilymph
Tympanic duct (scala tympani)
contains perilymph
perilymph
fluid that is similar to plasma, fills the vestibular and tympanic
ducts. Receives waves from oval window vibration.
helicotrema
the opening that connects the tympanic and vestibular canals at
the apex of the cochlea
cochlear duct (scala media)
filled with endolymph; separates cochlear cavity into upper
chamber (scala vestibuli) & lower chamber (scala tympani).
endolymph
fluid filling the cochlear duct
round window
membrane that waves from cochlea move through to return to
middle ear
, hair cells
audioreceptor cells: epithelial cells, mechanoreceptors in the
organ of corti (cochlear duct),
organ of corti
contains the auditory receptor cells
20000
Average number of hair cells per cochlea
sterocilia
stiff 'hairs' on hair cells that extend into the tectorial membrane.
When waves in the perilymph deform the basilar and tectorial
membranes, they bend.
basilar membrane
A structure that runs the length of the cochlea in the inner ear
and holds the auditory receptors, called hair cells.
tectorial membrane
A membrane located above the basilar membrane; serves as a
shelf against which the cilia of the auditory hair cells move
50-100
each hair cell has about __ stereocilia
longest cilium
When cilia bend towards the ___, the hair cell excites its neuron
hyperpolarizes, less transmitter, doesn't excite its neuron as
much