Neural Control & Coordination

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ÏÑÑËR ËÅR

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It consists of bony labyrinth & membranous labyrinth.

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Bony labyrinth is a cavity filled with perilymph.

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The membranous labyrinth consists of cochlea, otolith organs (saccule

& utricle) and semicircular canals.

ÇØÇHLËÅ (ØRGÅÑ ØF HËÅRÏÑG)

It is a coiled structure having

3

canals

-

upper

scala

vestibula,

middle

scala

media

and

lower

scala

tympani.

(NEET 2020)

Resting on the basilar membrane

and projecting into scala media

is complex receptor organ called

Organ of Corti. It consists of row

of sensory hair cells that act as

auditory

receptors.

The

hairs

(stereocilia) of these cells project

upwards and lie in contact with

tectorial membrane, which projects

above them.

Scala vestibula and scala media

are separated by Reissner’s

membrane. Scala media and

scala tympani are separated

by basilar membrane.

S. vestibula & S. tympani are

filled

with

perilymph

and

scala media is filled with

endolymph.

ÇØÇHLË Å (ØRGÅÑ ØF HËÅRÏÑG):

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The inner are also contains a complex system called vestibular

apparatus , located above the cochlea.

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Vestibular apparatus consists of 3 semicircular canals and otolith

organ.

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2 semicircular canals are vertical and one is horizontal. One end of each

canal has a bulging called ampulla. Inside it is a lump called crista

ampullaris (Odisha NEET 2019). Long cilia of cells of crista are grouped

together in a bundle (cupula).

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Otolith organ consists of utricle and saccule.