How We Hear

1. Sound travels as sound waves from the environment. Sound is collected by the outer ear and travels down the ear canal to the ear drum (tympanic membrane).

2. The sound wave makes the ear drum vibrate, which causes the three tiny bones (ossicles) in the middle ear to move.

3. The movement of these bones causes fluid in the inner ear or cochlea to move.

4. The motion of the fluid causes hair cells in the cochlea to bend. The hair cells change this movement into electrical impulses.

5. The electrical impulses are transmitted to the auditory nerve and up to the brain where they are interpreted as sound.