How do we hear?

The ear consists of outer ear, middle ear and inner ear:

Outer ear (external ear): Outer ear consists of pinna (auricle), external auditory canal (out ear canal) and the tympanic membrane (eardrum). The outer ear helps funnel sound into the ear canal and directs sounds into the middle ear. The outer ear also contains glands that secrete cerumen (earwax), to help protect the ear and provide protection against germs.

Middle ear: Middle ear consists of ossicles - malleus, incus, and stapes - to help amplify sound vibration and transmit the vibration into the inner ear. Middle ear also consists of an eustachian tube, a canal that connects the middle ear to the back of the nose. The eustachian tube helps equalize the pressure between your middle ear and the outside environment.

Inner ear: The inner ear consists of cochlea, vestibule and semicircular canals. Cochlea is the hearing organ. When sound vibration is transmitted into the inner ear, the fluid in the cochlea starts to ripple and moves the tiny hair cells in it. The hair cells vibrate, then send electrical impulses via the auditory nerve to the brain for processing and interpretation. The vestibule and semicircular canals are responsible for balance. They detect the speed and the direction of your movement and send signals to the brain.

How do we hear

Sound waves enter the outer ear and travel through the outer ear canal and tympanic membrane (eardrum) into the middle ear space. The eardrum vibrates when sound vibrations hit it and send these vibrations to the ossicle, the three small bones in the middle ear. These small bones amplify the sound vibrations and send the amplified vibrations into the cochlea in the inner ear. The tiny hair cells in the cochlea get excited and send the collected information to the brain via the auditory nerve. The brain then processes and interprets the nerve impulses as sound.