Sound is collected by the pinna (the visible part of the ear) and directed through the external ear canal. The sound makes the eardrum vibrate, which in turn causes a series of three tiny bones (the hammer, the anvil, and the stirrup) in the middle ear to vibrate. The vibration is transferred to the snail-shaped cochlea in the inner ear; the cochlea is lined with sensitive hairs which trigger the generation of nerve signals that are sent to the brain.
external ear canal - the tube through which sound travels to the eardrum.
pinna - (also called the auricle) the visible part of the outer ear. It collects sound and directs it into the external ear canal.
anvil - (also called the incus) a tiny bone that passes vibrations from the hammer to the stirrup.
eardrum - (also called the tympanic membrane) a thin membrane that vibrates when sound waves reach it.
stirrup - (also called the stapes) a tiny, U-shaped bone that passes vibrations from the stirrup to the cochlea. This is the smallest bone in the human body.
hammer - (also called the malleus) a tiny bone that passes vibrations from the eardrum to the anvil.
Eustachian tube - a tube that connects the middle ear to the back of the nose; it equalizes the pressure between the middle ear and the air outside.
cochlea - a spiral-shaped, fluid-filled inner ear structure; it is lined with cilia (tiny hairs) that move when vibrated and cause a nerve impulse to form.
semicircular canals - three loops of fluid-filled tubes that are attached to the cochlea in the inner ear. They help us maintain our sense of balance.
oval window- (or vestibular window) is a membrane-covered opening which leads from the middle ear to the vestibule of the inner ear.