The Ear
The ear is the sensory organ that allows us to
hear.
It converts airborne sounds waves into nerve
impulses that are decoded by the brain
The Ear
*
Parts of the Ear
Outer ear (external)
• ______________________
- This is the visible part of the ear.
2) _______________________
- It gathers sound waves from the environment and
directs them along the auditory canal
– is 3.75 cm long
– Has walls lined with hairs and glands that secrete
wax  these prevent foreign particles from
entering the ear
– Ends at the tympanic membrane or eardrum
*
3) The middle ear
• The eardrum or tympanic membrane
• Three small bones; called the hammer, anvil and stirrup.
(________ -hammer, ________- anvil, ________- stirrup)
• It is linked to the Eustacian tube; ot equalizes the air
pressure on the two sides of the eardrum. (ear pops_
4) The inner ear
• a fluid filled cavity in the temporal bone.
• Contains the ____________________ and ___________.
FYI
The takeoff or landing of an airplane, the acceleration of an elevator,
deep-sea diving, or driving up a steep hill in a car all bring about
changes in air pressure which may be experienced as discomfort in the
ears. This feeling is the result of increased pressure being exerted on
the eardrum, which causes it to bulge on one side or the other,
depending where the pressure is higher. Usually the act of yawning,
swallowing, or sneezing opens the Eustachian tube, equalizing the
pressure on the two sides of the eardrum and relaxing this membrane.
Cochlea
• spiral-shaped
• fluid-filled inner ear structure
• lined with cilia (tiny hairs) that move when
vibrated and cause a nerve impulse to form
• The axons of cilia form the auditory nerve that
sends auditory signals to the brain
• Ear
• Cochlea
• Auditory
Nerve
• Brain
•
•
•
•
Ear
Receiver
Conductor
Auditory Nerve
Cochlea
Transformer
Brain
Analyzer
Transformer
Analyzer
Conductor
Receiver
Chain Reaction of Hearing
sound waves  the auricle  the auditory
canal  vibrations  the eardrum  the
three bones of the middle ear  cilia move
(inside cochlea)  nerve impulse is
triggered in the auditory nerve  the center
for hearing in the brain  hearing
Hearing Loss & Prevention
• 3 Main causes of hearing loss:
1. ______________
2. __________________________
3. ___________________
___________________
(eardrum, small bones of the middle ear)
Review Questions
1)
2)
3)
4)
5)
6)
7)
What part of the ear gathers sound waves in the air?
______________________________________________
What name is given to the structure that connects the ear
to the nose? ____________________________________
How does the ear protect itself from unwanted incoming
particles? ______________________________________
What two structures compose the inner ear?
______________________________________________
What structure contains the hearing receptor cells?
______________________________________________
Which part of the ear houses the nerve endings for
hearing? ______________________________________
When does a person experience the sensation of
hearing? ______________________________________
Internet Resources
– Slideshow:
• http://www.nlm.nih.gov/medlineplus/tutorial
s/hearingloss/htm/_no_50_no_0.htm