Parts and Functions of the Ear
The outer ear is the external part of the ear, collects sound waves and passes them into the ear. It is a visible portion of the ear that serves as a protective organ for the eardrum. It has three parts-the pinna, auditory canal and ear drum.
Pinna determines the source of sound and amplifies frequency of sound. Auditory canal is lined with skin and hairs which protect the eardrum by trapping dirt and foreign bodies. Modified sweat glands secrete cerumin to keep the canal moist. Eardrum receives the sound waves and transforms the sound energy into the mechanical energy.
Middle ear collects the sound waves from the outer ear in the form of pressure waves. The middle ear is involved in transmitting sound from the outer ear to the inner ear.The middle ear is an air-filled cavity and consists of three bones -malleus, incus, stapes and Eustachian tube.
The Eustachian tube functions to equalize air pressure of the eardrum. The vibrations from the ear drum are transmitted through malleus via incus and to stapes and reach the oval window which leads to the inner ear.
The inner ear is small and is filled with a water-like substance and comprises both hearing and balancing organs.Inner ear contains the vestibule, semicircular canals, and the cochlea. The vestibule has oval window and the round window which connects the middle and inner ear and maintains equilibrium.
Semicircular Canals are fluid-filled loops attached to the cochlea and helps in maintaining the balance. The cochleais the site of the sense organs for hearing. In cochlea the hair-like nerve cells respond to various frequencies of vibrations and lead to generation of electrical impulses. Auditory Nerve passes electrical impulses to the brain.
The semicircular canals and vestibule present in inner ear functions to sense movement (acceleration and deceleration) and static position of the body.
