PSYC 212 Study Guide - Quiz Guide: Incus, Middle Ear, Oval Window

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20 Jul 2016
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The vibrations are picked up by the pavillon of the outer ear.
-The vibrations are transmitted to the middle ear- where there is ossicles-
The vibrations first go to the malleus ossicles, then the incus ossicles, then
the stapes ossicles.- the stapes acts like a piston that compresses the fluids
of the inner ear.
-Cochlea- main auditory organ- has 15-20,000 hair cells that detect
vibrations of the liquid. It innervates neural impulses that are sent to the
brain VIA the auditory nerve.
-Conduction hearing loss- comes from earwax blocking the canal to the
middle ear or failure of conduction of the ossicles or fluid in the middle ear.
-Sensorineural hearing loss- the destruction of hair cells in the cochlea- due
to aging, can be genetic, or the consequence of repeated exposure to very
loud sound.
-Stapes transfer force to the oval window.- From there, sound moves to the
round window- High frequencies are encoded at the base
and low at the apex.
-This lead to the tonotopic map along the base of the basilar membrane.
Basilar membrane vibrates in response to sound- hair cells are between the
two membranes- stimulated by the shearing force.
Fourier transform- Terms Time into a function of frequency.
-Mapping between two sets of data- changes info. In the time domain into
info. In the frequency domain- the data look diff. and can vary in data, but it
represents the same data.
-Time domain can be converted to frequency since the sinusoids can be
described by their frequency, amplitude and phase. – those are the only
info. You need to describe the signal.
-Sinusoids are just the lines on the spectrogram. – only curve that does not
change shape. – Since it doesn’t change shape we have a system that can
be described by changes in frequency and shifting in phase at any given
frequency.
The ossicles move internal fluid against a membrane.
How sound works- FREQUENCY- The number of waves that pass a certain
point in a given time frame.
High pitch- shorter waves moving in and out more quickly.
Fewer/slower fluctuations result in a lower pitch.
-AMPLITUDE- The difference between the high and low pressures created in
the air by that sound waves.
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External/Middle/Inner Ear.
-External and middle are only involved with hearing.
-Inner ear- hearing and maintain equilibrium.
External ear- Pinna/Auricle: Main function is to catch sound waves and
passes them along deeper into the ear.
-Once the sound is caught it is funnelled into the external acoustic
Meautus(auditory canal)- and towards the middle/ ear,
Tympanic membrane- boundary between the external and internal ear.
When the sound waves collide with the ear drum, they push the tympanic
membrane back and forth, making it vibrate. So it can pass the vibrations
on to the tiny bones in the middle ear, the ossicles.
Tympanic cavity- relay station between the outer and inner ear.-Main job is
to amplify those sound waves so they’re stronger when they enter the inner
ear.
-Inner ear moves sound through a special fluid, not through air.
The tympanic cavity focuses the pressure of sound waves so that they’re
stronger to move the fluid in the inner ear.
The cavity does this using the 3 osicles inside the cavity.
The malleus, incus and stapes.
One part of the malleus is connected to the inner ear drum and moves back
and forth when the drum vibrates.
And is attached to the incus, which is attached to the stapes.
Together they conduct the sound vibrations to the superior oval window. –
where they set that fluid in the inner ear, into motion.
Job of the cochlea: Turn those physical vibrations into electrical impulses the
brain can identify as sounds. And two- help maintain your equilibrium.
The cochlea has 3 main chambers inside of it(cross-section):
-Scala vestibule.
-Scala media.
-Scala tympani.
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