Anatomy and Physiology of the Ear

What is the ear?

The ear is the organ of hearing and balance. The parts of the ear include:

• External or outer ear, consisting of:
• Tympanic membrane (eardrum). The tympanic membrane divides the external ear from the middle ear.
• Middle ear (tympanic cavity), consisting of:
• Inner ear, consisting of:

How do you hear?

Hearing starts with the outer ear. When a sound is made outside the outer ear, the sound waves, or vibrations, travel down the external auditory canal and strike the eardrum (tympanic membrane). The eardrum vibrates. The vibrations are then passed to 3 tiny bones in the middle ear called the ossicles. The ossicles amplify the sound. They send the sound waves to the inner ear and into the fluid-filled hearing organ (cochlea).

Once the sound waves reach the inner ear, they are converted into electrical impulses. The auditory nerve sends these impulses to the brain. The brain then translates these electrical impulses as sound.