Transcript Section 3 Notes

• Sound travels in
waves caused by
vibrations.
• Absolute Threshold
is 0 dB
• Above 85dB for
prolonged periods
leads to hearing
loss
Pitch
Pitch—how high or low a sound is
Depends on its frequency, or the number of
cycles per second—the more cycles per
second, the higher the pitch
Loudness
Loudness—determined by the height, or amplitude, of
sound waves. The higher the amplitude of the wave,
the louder the sound.
•Measured in decibels (dB)
•Zero dB is considered the threshold of hearing
(a watch ticking 20 feet away in a very quiet
room)
The Ear
•Outer ear—shaped to capture sound waves and to
transmit sound to the brain
•Eardrum is the gateway from the outer ear to the
middle ear
The Ear cont…
•Middle ear—the hammer, the anvil, the stirrup
(smallest bone in the body). These bones vibrate
and transmit sound to the inner ear.
•Inner ear—consists of the cochlea (Greek word
for “snail”)—a bony tube that contains fluids as
well as neurons that move in response to the
vibrations of the fluids
•Auditory nerve—the cranial nerve that carries
sound from the cochlea of the inner ear to the
brain
THE EAR
2 TYPES
CONDUCTIVE
SENSORINEURAL
Middle Ear
Inner Ear
Older
Neurons in
the Cochlea
Hearing Aids
Disease
Noise
*May be inherited or caused by disease, injury,
or old age (approx. 2 million Americans)
*Conductive Deafness—occurs because of damage to the
middle ear, prevents people from hearing sounds that are not
loud enough. Hearing aids often help by providing the
amplification that the middle ear does not. Often seen in older
people.
*Sensorineural Deafness—caused by damage to the inner ear,
prevents people from perceiving sounds of certain frequencies.
Most often, the neurons in the cochlea are destroyed. Can be
caused by damage to the auditory nerve, either by disease or
through prolonged exposure to very loud sounds.
WORLD TODAY
• Mainstreamed
• Interpreters
• ASL
• Closed
Captioned
• https://www.youtube.com/watch
?v=X-DxGoIVUWo