Transcript Parts and Functions of the Ear

Parts and Functions of
the Ear
What is sound?
• Sound is the vibration of air
molecules. Sound waves refer
to the “ripples” created as the
sound vibrations move out
from the source.
The hearing mechanism
Regions of the ear
a. The pinna
The function of the pinna is to
capture sound waves.
g. The auditory canal
The auditory canal has two
functions:
• 1. To send sound waves to
the middle ear.
• 2. To keep the ear clean of
debris.
a) cilia: hair
b) cerumen: ear wax
f. The Tympanic Membrane
The tympanic membrane has
two functions:
1. Seals off the middle ear.
2. Vibrates the ossicles (ear
bones).
The ossicles
the three smallest bones in the
body
• h. Malleus
(hammer)
• i. Incus
(anvil)
• j. Stapes
(stirrup)
• (MIS)
Ligaments connect the malleus
directly to the back of the tympanic
membrane.
The stapes taps the cochlea to
transmit sound vibrations to the
inner ear
.
e. Eustachian tube
• Has two functions:
• Equalizes air pressure in the
middle ear
• Drains the middle ear
b. semicircular canal
c. cochlea
• The semicircular canals maintain
balance.
• The cochlea changes sound vibrations
to nerve impulses.
The cochlea is spiral, hollow
chamber of bone filled with
liquid and thousands of
nerve endings.
These nerve endings are triggered
by vibrations sent through the
liquid-filled cochlea. As the nerves
exit the cochlea they combine
together to become the auditory
nerve.
d. The auditory nerve
The auditory nerve is a
collection of nerves sending
nerve impulses to the brain.