Transcript Special Senses: The Ear

SPECIAL SENSES:
THE EAR
Functions of the Ear
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Hearing
Equilibrium (Balance)
External Ear Anatomy
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Involved in hearing only
Pinna – traps sound
Ear canal
 Lined
with skin
 Ceruminous glands
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Tympanic Membrane
Middle Ear Anatomy
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Tympanic cavity
Eustachian tube
Ossicles
 Malleus
(hammer)
 Incus (anvil)
 Stapes (stirrup)
Inner Ear Anatomy
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Organs for hearing and balance
Filled with perilymph
Cochlea
Vestibule
Semicircular canals
Inside the Cochlea
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Oval window
Organ of Corti
 Endolymph
 Hair
cells
 Membranes
 Cochlear nerve
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Round window
Hearing
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Pinna collects sound
Sound waves vibrate tympanic membrane
(eardrum)
Eardrum movement is transferred to ossicles
Ossicles vibrate oval window
of cochlea
Hearing
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Stapes vibrates the oval window.
Movement of oval window moves fluid in
cochlea.
Fluid movement
vibrates membranes in
Organ of Corti
Membrane movement
bends hairs
Bent hairs cause
action potential
Hearing
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Action potential travel through auditory nerve
to brain!
You hear something!
Hearing
Hearing
Hearing Damage
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Tinnitus
Deafness
Cochlear Implants
Balance
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In the vestibule:
 Endolymph
 Hair
cells
 Otoliths
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Senses head
movement
Balance and Motion
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In semicircular canals:
 Endolymph
 Hair
cells
 Cupula
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Senses acceleration