SPECIAL SENSES: HEARING &
EQUILIBRIUM
MARTINI, FUNDAMENTALS OF ANATOMY &
PHYSIOLOGY, 9TH EDITION, CHAPTER # 17
Exercise # 22
NOTE:
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THIS IS A STUDY GUIDE, NOT AN ALL INCLUSIVE REVIEW.
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THERE MIGHT BE THINGS NOT COVERED BY
THIS STUDY GUIDE THAT MIGHT BE ASKED IN
YOUR PRACTICUMS /
QUIZZES.
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STUDENTS ARE RESPONSIBLE FOR READING
THEIR TEXBOOK (S) AND FOR ALL THE MATERIAL
COVERED DURING THE LABORATORY PERIOD,
AS PER THE COURSE SYLLABUS
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OBJECTIVES
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Identifying the structures of the ear and
describe their functions.
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EXTERNAL EAR
MIDDLE EAR
INNER, OR INTERNAL EAR
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EXTERNAL EAR
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Pinna or auricle- to capture the sound waves
External auditory canal-to focus & direct the sound waves
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Ceruminous glands (lining the external auditory canal)
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f- to produce waxy material
To avoid foreign matters to go inside
Tympanic membrane- to transmit the sound waves
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MIDDLE EAR
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Ossicles (3 little bones)- malleus, incus & stapes
F- to transmit the sound waves
Pharyngotympanic or auditory or eustachian tube
F- to equalize the pressure inside & outside the
tympanic membrane
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INNER OR INTERNAL EAR
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The bony labyrinth -it has 3 parts- vestibule,
semicircular canal & cochlea
It surrounds the membranous labyrinth
It contains the perilymph
Perilymph (pink in model)-to transmit sound waves
Membranous labyrinth (grey in model)- it Contains the endolymph
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Endolymph- to transmit sound waves
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Vestibule- balance & equilibrium
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It contains the utricle & sacule
Utricle & sacule- contain the macula
F- sensations of gravity & linear acceleration
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Semicircular canals- sense of dynamic balance
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Ampulla- swollen area at the end of the
Semicircular canal that contains the Crista
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Crista- contains sensory receptors for dynamic balance
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INNER EAR: COCHLEA
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It contains receptors for hearing
It has 3 ducts or chambers
vestibular duct (scala vestibuli)-pink in model
Upper duct that contain perilymph
Cochlear duct (scala media)-blue in model
Middle duct that contains endolymph
Tympanic duct (scala tympani)- green in model
Lower duct that contains perilymph
Oval window (at the base of the stapes)F- to transmit sound to the inner ear
Round window- it separates the perilymph of the
cochlear duct from air spaces of the middle e
F- it releases excess pressure
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INNER EAR: THE ORGAN OF CORTI
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3 membranes around the organ of corti
Vestibular membrane (upper one)- to separate
the cochlear duct from scala vestibuli
Tectorial membrane (in the middle of the
cochlear duct)- it stimulates hair cells
Basilar membrane (bottom one)- to transmit
the vibration to the hair cells
Organ of corti- it contains the hair cells that
produce the hearing signal
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REMEMBER!
GO TO THE TUTORING ROMM
AND PRACTICE WITH MODELS.
ROOM 3326.
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