Anatomy of ear

Anatomy and Physiology of the Ear

The ear is the organ of balance and hearing. The ear includes many parts, following are these parts:

  • The external or outer ear, consisting of:
    1. Pinna or auricle. It’s the outside part of the ear.
    2. External auditory canal or tube. This is the tube which connects the outer ear to the inside or middle ear.
  • Tympanic membrane (eardrum). The tympanic membrane divides the external ear from the middle ear.
  • Middle ear (tympanic cavity), consisting of:
    1. Ossicles. Three small bones that are connected & transmit the sound waves to the inner ear. These bones are called:
      • Malleus
      • Incus
      • Stapes
    2. Eustachian tube. A canal which links the middle ear with the back of the nose. The eustachian tube helps to equalize the pressure in the middle ear. Equalized pressure is needed for the appropriate transfer of sound waves. The eustachian tube is lined with mucous, just like the inside of the throat and nose.
  • The inner ear, consists of:
    1. Cochlea. This contains the nerves for hearing.
    2. Vestibule. This contains receptors for balance.
    3. Semicircular canals. This contains receptors for balance.

How do you hear?

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

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

See Also
The Outer Ear Anatomy