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How we hear

The ear can be divided into three main sections, the external, middle and inner ear. Sound waves are collected by the external ear, the pinna, and travel down the ear canal where they make the ear drum vibrate. The movement crosses the middle ear via three tiny bones to the inner ear. In turn the nerves are stimulated and send signals to the brain which interprets them as sounds.

How We Hear1. Sound is collected by the ear and funneled through the ear canal to the eardrum.

2. The eardrum converts incoming sound into vibrations.

3. The chain of bones (ossicles) is set into motion by the vibrations, passing them on to the inner ear (cochlea).

4. The fluid in the cochlea begins to move, stimulating the delicate hair cells. The hair cells inturn create electrical signals which are sent along the the auditory nerve to the brain. Hair cells at the top end (apical) of the cochlea respond to low pitch sound information, and hair cells at the other end (basal) respond to high pitch sound information.

5. The auditory nerve transmits the electrical signals to the brain (auditory cortex) which learns to interpret the signals as sounds.

Picture and text courtesy of MED-EL. © MED-EL 2005