EAR ANATOMY
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.
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OUTER EAR
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.
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MIDDLE EAR
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.
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INNER EAR
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.
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