Ears
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Warm up
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What is the condition called where the eye is egg shaped
instead of round?
What is the colored portion of the eye?
What is the window of the eye?
What does the conjunctiva line?
Where is the optic disk located?
What lies directly behind the pupil?
What colors are difficult to see if you are color blind?
If you could not see well at night, what eye structure would
be impaired?
What is the eye condition called where the lens is cloudy?
What eye disorder would you have if your central vision
was distorted or dark?
Structure and
functions of the ears
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Structures of the ears
 External
ear
 Middle ear
 Also known
as the
tympanic
cavity
 Inner ear
 Also known
as the
labyrinth
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Understanding the structures and
functions of the ear
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External ear
PINNA (AURICLE)
– outer ear, collects
sound waves
EXTERNAL
AUDITORY
CANAL – ear canal
CERUMEN –
earwax, protects the
ear
TYMPANIC
MEMBRANE – ear
drum, separates
outer and middle
ear
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Understanding the structures and
functions of the ear
Middle ear
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Cavity in temporal bone
Connects with pharynx by
EUSTACHIAN TUBE –
which equalizes pressure
in the middle ear with
outside atmosphere
Ossicles- Bones in middle
ear that transmit sound
waves from ear drum to
inner ear
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MALLEUS (hammer)
INCUS (anvil)
STAPES (stirrup)
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Understanding the structures and
functions of the ear
Inner ear
 Contains spiral
shaped organ of
hearing – the
COCHLEA
 The cochlea contains
a membranous tube,
the cochlear duct –
which is filled with
fluid that vibrates
when sound waves
are transmitted by
the stapes
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Understanding the structures and
functions of the ear
Inner ear
 ORGAN OF CORTI –
delicate hairlike cells that
pick up vibrations of fluid
and transmit them as a
sensory impulse along the
auditory nerve to the brain
 SEMICIRCULAR
CANALS – three structures
in the inner ear, contain
liquid that is set in motion
by head and body
movements – impulses sent
to cerebellum to help
maintain body balance
(equilibrium)
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Ears
Name the structures…
 Review
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Pathway of Hearing
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Sound
Outer Ear
External Auditory
Canal
Tympanic Membrane
Ossicles (malleus,
incus, stapes)
Oval Window
Cochlear- Organ of
corti
Auditory Nerve
Brain- Cerebral cortex
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Decibles
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A measurement of sound level
https://www.youtube.com/watch?v=uAd2
BUB6XqQ
 Hearing Activity- Name the following
sounds on your handout
 http://www.crickweb.co.uk/ks1science.html
#sound1f
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3.04 Understand the functions and
disorders of the sensory system
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Healthy Hearing
How do you protect your hearing?
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Disorders of the ear
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Disorders of the ear
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Disorders of the ear
External otitis
• Cause- Commonly known
as “swimmer’s ear”
Infection in the external
auditory canal- bacterial or
fungal
• Symptoms- Fever, pain in
ear and decreased hearing or
loss.
• Treatment- Antibiotic drops
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Disorders of the ear
Otitis media
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Cause- Infection of the middle
ear. Often a complication of a
common cold in children
Symptoms- Fever, ear pain, pus.
Child will pull at ears. Can be
one side or both.
Treatment- antibiotics
 If chronic or if fluid builds up
– MYRINGOTOMY (opening
in the tympanic membrane)
with tubes inserted will
relieve the pressure
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Disorders of the ear
Otitis media
http://www.medicinen
et.com/anatomy_of_an_
ear_infection_pictures_s
lideshow/article.htm
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Disorders of the ear
Otosclerosis
 Cause- Excess bone
growth in the middle earsusually the stapesHereditary- Hardening
 Symptoms- Decreased
hearing and sometimes
deafness.
 Treatment- Stapedectomyreplacing the stapes with a
plastic or wire implant.
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Disorders of the ear
Otosclerosis
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Disorders of the ear
Meniere’s disease
 Cause- abnormal
volume or composition
of fluid in the inner ear
labyrinith.
 Symptoms- Vertigo,
hearing loss, tinnitus
 Treatment- No cure.
Motion sickness
medications, nausea
medicine.
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Disorders of the ear
Tinnitus- ringing in the ears.
It’s a symptom not a
disorder. Can be caused by
loud noises
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Disorders of the ear
Presbycusis
(Hard of Hearing)
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Cause- Degeneration of the inner
ear. Gradual hearing loss in both
ears due to aging.
Symptoms- Loss of hearing
especially high pitched sounds,
women’s voices, tinnitus.
Treatment- Hearing aids
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Disorders of the ear
Conductive Hearing Lossoccurs when there is a
problem conducting sound
waves anywhere along the
route through the outer ear,
tympanic
membrane (eardrum),
or middle ear (ossicles).- Ear
wax impacted in ears
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Disorders of the ear
Sensorineural Hearing Loss- a
type of hearing loss in which the
root cause lies in
the vestibulocochlear nerve, the
inner ear, or central processing
centers of the brain.
Sensorineural hearing loss can be
mild, moderate, or severe,
including total deafness. Can
happen during development or
nerve damage after birth.
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Testing for hearing loss
http://www.youtube.com/watch?v=7
BQFKnP-7Qg
Rinne test
Weber test
Compare these two tests.
How are they diagnostic?
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Processing
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Labeling #3
Structure, Functions and
Disorders of the Ear
The End
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