1. SPECIAL SENSES: HEARING & EQUILIBRIUM
MARTINI, FUNDAMENTALS OF ANATOMY & PHYSIOLOGY, 9TH EDITION, CHAPTER # 17
Exercise # 22

2. NOTE:
THIS IS A STUDY GUIDE, NOT AN ALL INCLUSIVE REVIEW.
THERE MIGHT BE THINGS NOT COVERED BY THIS STUDY GUIDE THAT MIGHT BE ASKED IN YOUR PRACTICUMS /
QUIZZES.
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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3. Identifying the structures of the ear and describe their functions.
OBJECTIVES
Identifying the structures of the ear and describe their functions.
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4. EXTERNAL EAR MIDDLE EAR INNER, OR INTERNAL EAR
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5. EXTERNAL EAR Pinna or auricle- to capture the sound waves
External auditory canal-to focus & direct the sound waves
Ceruminous glands (lining the external auditory canal)
f- to produce waxy material
To avoid foreign matters to go inside
Tympanic membrane- to transmit the sound waves
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ALFONSO A. PINO. MD.

7. MIDDLE EAR 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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ALFONSO A. PINO. MD.

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ALFONSO A. PINO. MD.

10. INNER OR INTERNAL EAR 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
Endolymph- to transmit sound waves
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12. Vestibule- balance & equilibrium
It contains the utricle & sacule
Utricle & sacule- contain the macula
F- sensations of gravity & linear acceleration
Semicircular canals- sense of dynamic balance
Ampulla- swollen area at the end of the
Semicircular canal that contains the Crista
Crista- contains sensory receptors for dynamic balance
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ALFONSO A. PINO. MD.

14. INNER EAR: COCHLEA 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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ALFONSO A. PINO. MD.

16. INNER EAR: THE ORGAN OF CORTI
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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19. REMEMBER! GO TO THE TUTORING ROMM AND PRACTICE WITH MODELS. ROOM 3326.
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