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A Handbook of Biology

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It has 3 divisions: External ear, middle ear & inner ear.

It is the organ for hearing & balancing and thus are called

stato-acoustic organ.

ËXTËRÑÅL ËÅR

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Consists of pinna (ear lobe) & auditory meatus (ear canal).

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At the opening of ear canal, hairs are seen.

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Ear canal contains ceruminous glands (modified sebaceous glands).

They secrete wax (cerumen).

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Wax and hairs prevent entry of foreign objects like insects.

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Ear canal ends in tympanic membrane (Tympanum or ear drum). It is a

semi-transparent membrane covered by a thin layer of skin on its outer

surface and by mucous membrane on the inside.

MÏDDLË ËÅR

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Middle ear consists of tympanic cavity and ear

ossicles.

Tympanic cavity is an air filled space that separates

the external and inner ear portions.

An auditory tube (Eustachian canal) connects middle

ear to the pharynx. It maintains an equal pressure on

either side of the eardrum.

(NEET 2020)

Ear ossicles include 3 small bones namely Malleus,

Incus and Stapes. Malleus is attached to tympanum.

Stapes is the smallest bone of the body. It is attached

to membrane of oval window of inner ear. (NEET 2020)