Introduction of ear

1. EAR
DEPARTMENT OF HEALTH PROFESSIONAL TECHNOLOGIES
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2. EAR
 The organ of hearing and balance.
 Contains ear receptors, sensitive to sound vibrations between
frequency of 20Hz to 25,000Hz
 FUNCTION: transmit and transduce sound to brain through
parts of ear.
 DIVISIONS:
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Ear
Outer ear Middle Ear Inner ear

3. Structure of Ear:3

4. INNER EAR:
 Auris interna, innermost part of the ear
 Another name: Labyrinth of the ear
part of the ear, containing sense organs of hearing
and equilibrium
 Consists of: bony labyrinth & membranous labyrinth
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5. BONY
LABYRINTH
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Bonylabyrinth
Vestibule
Semicircular
canals
cochlea

6. 1. VESTIBULE:
 Central chamber of the labyrinth
 Location: behind the cochlea and in
front of semicircular canals
 Structure: On lateral side, oval
window lies and inside of medial
wall, two recesses are present i.e
saccule (spherical) & utricle
(elliptical)
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7. 2. SEMICIRCULAR CANALS
 Three in numbers: lateral, posterior and superior
 Lies at right angles to each other
 Each canal has an ampullated end (dilated end) and
non ampullated end.
 Non ampullated ends of PSCC & SSCC unite to form
a common channel called Crus commune
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8. 3. COCHLEA
 APPERANCE: snail shell. Spiral shaped
cavity.
 Coiled tube making 2.5 to 2.75 turns
round.
 The bony cochlea has three
compartments called Scalae:
● scala vestibule
● scala tympani
● scala media
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9. MEMBRANOUS LABYRINTH:
 A continuous system of ducts and sacs
within a bony labyrinth.
 PARTS: It is composed of:
i) cochlear duct
ii) saccule
iii) utricle
iv) 3 semicircular ducts
v) endolymphatic duct
 Endolymphatic duct is formed by the union of
two ducts, one each from the saccule and the
utricle.
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10. INNER EAR FLUIDS:
 Two major fluids:
i) Perilymph
ii) Endolymph
PERILYMPH:
 it fills the space between
membranous and bony
labyrinths
 It is rich in Na ions
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11. ENDOLYMPH:
 Fluid which fills the membranous labyrinth
 Rich in K (potassium) ions
INNERVATION:
 Innervation to the inner ear is provided by 8th cranial nerve i.e
vestibulocochlear nerve
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12. BLOOD SUPPLY OF LABYRINTH:
 ARTERIAL SUPPLY:
is through the following artery
 labyrinthine artery (branch of anterior-inferior cerebellar artery)
 VENOUS DRAINAGE:
is through 3 veins:
 Internal auditory vein
 Vein of cochlear aqueduct
 Vein of vestibular aqueduct
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13. THANK YOU
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