There is a pair of ears to hear. They are located on sides of head. Study of ear in all aspects is called otology.
Ear shows 3 parts :-
External , internal and middle.
It has 2 parts – Pinna and external Auditory meatus.
(Pinna – collects vibrations in the air which produce sound)
(external auditory meatus – it leads up to ear drum. There are many fine hairs and loax-secreting sebaceous glands in the skin of the Pinna and meatus. )
It contains there ossicles (bones) called
(1) Malleus (2) incur (3) stapes
These bones are attaced to each other in a chain manner. These ossicles increases efficiency of sound waves to the inner ear.
It is filled up with fluid and also called labyrinth.
(2) membranous labyrinth- membranous labyrinth contains fluid called endolymph and furthec divided into 3 parts.
(2) semicircular duets
(3) cochlear duets.
Coiled portion of labyrinth is called cochlea. It is a coiled cavity of inner ear. Hare sound vibrations are converted into nerve impulse.
Eustachian tube – it connects the middle ear caving with the pharynx. The Eustachian tube helps in equalizing the pressures on both sides of ear drum.
Tympanum/tympanic surface:- it is called ear drum. A thin surface that separates the outer ear from the air to the malleus.
Organ of corti - it is located on basilar membrane which contain hairs cells that act as auditory receptors.
Mechanism of hearing
The external ear receives sound wanes and directs them to the ear drum. Ear drum vibrates due in response to sound wanes and these vibrations are transferred through ear ossicles ( malleus, incus and stapes) to oval window to fluid of cochlea. Now if further causes sound movements in basilar membrane. These movements of the basilar membrane bend the hair cells of organ of corti. In this way, these impulses are transmitted by the afferent fibers through auditory nerves to auditory cortex of brain where impulse are analyzed and sound is recognized.
Care of ears :-
(1) Do not rub the external ear canal with hard objects like pencils, hairpins etc.
(2) Wax in ext ear protects the ear drum from drying up or damaged by water.