NSC-2201 Lecture Notes - Lecture 11: Eustachian Tube, Oval Window, Vestibular Membrane
25 Feb 2017
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Vestibular System = our sense of balance
1. This informs us without our head and brain moving
Sounds are made of compressed air waves, known as sound waves
1. The Frequency measures how often they come, as known in cycles per second
2. Look like waves with
compressed and rarified
patches
a. The frequency is
the number of
cycles, or
compressed
waves, per second
b. The Pitch is determined by the frequency. Higher pitched sounds are higher on a piano
per say
b.i. Humans can hear from 20 to 20,000 Hz
c. The Intensity is determined by the amplitude, or difference in beads from the high to low
rarified patches.
c.i. Intensity is known as the loudness.
c.ii. All sound is just a combination of pitch (frequency) and intensity (amplitude)
3. Pinna = the funnel that helps us collect sound. Maximizes surface area on the ear
4. Auditory Canal Compresses the Sound from the Ear
5. From there it hits the tympanic membrane and vibrates it
6. It vibrates and amplifies sound on the three ossicles: the malleus,
incus, and stapes (hammer, anvil, stirrup)
7. Then it pokes through the oval window and vibrates the cochlea,
which changes the sound into neuronal signals. ;
a. Let’s review that process
a.i. Sound waves hit tympanic membrane, vibrating it.
Then the vibrate three bonds and oval window and
then cochlea transmitting to neuronal signals.
a.i.1. The Eustachian tube in the ossicles
a.i.1.a. Malleus (Hammer)
a.i.1.b. Incus (Anvil)
a.i.1.c. Stapes (Stirrup)
a.i.2. ...This tube connects the space of the ossicles to our mouth
a.i.2.a. When closed, if pressure decreases by say, going up in
the air, then the tympanic membrane bulges out painfully
a.i.2.a.i. Opening of the tube through yawning, chewing tends to
make pressure equal once more.
a.ii. The Cochlea is filled with fluid, so it is harder to move. Sound waves hit the
tympanic membrane. The space decreases and the ossicles vibrate to increase the
pressure.
b. The attenuation reflux is when the muscles contract in order to better understand during
sound. They contract more during low frequencies.
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Document Summary
Vestibular system = our sense of balance: this informs us without our head and brain moving. Higher pitched sounds are higher on a piano per say b. i. Humans can hear from 20 to 20,000 hz: the intensity is determined by the amplitude, or difference in beads from the high to low rarified patches. c. i. All sound is just a combination of pitch (frequency) and intensity (amplitude) c. ii: pinna = the funnel that helps us collect sound. Maximizes surface area on the ear: auditory canal compresses the sound from the ear, from there it hits the tympanic membrane and vibrates it. Then the vibrate three bonds and oval window and then cochlea transmitting to neuronal signals. a. i. 1. The eustachian tube in the ossicles a. i. 1. a. a. i. 1. b. a. i. 1. c. This tube connects the space of the ossicles to our mouth a. i. 2. a. When closed, if pressure decreases by say, going up in the air, then the tympanic membrane bulges out painfully a. i. 2. a. i.
