The Outer Ear

• The outer ear is the part of the ear that everyone sees. It is called the "pinna" or "auricle." In Latin, pinna means wing. It is made of both soft and hard cartilage. The outer ear is important because it helps capture sounds from a certain distance and direction and directs the sounds into the ear. The outer ear also acts as a filter for sounds, and it determines the location and source of sounds.
  
  

Ear Canal and Ear Drum

• As sounds make their way into the outer ear, they next travel through the ear canal, which is also called the "external auditory meatus." The ear canal continues to further filter sounds. It is a short, crooked tube that ends at the eardrum. The ear canal is about 2.4 cm long. Sounds continue to travel further into the ear and then into through the eardrum. The eardrum is a thin, tightly stretched membrane. It is also called the "tympanic membrane." The eardrum vibrates when responding to pressure change.
  
  

Middle Ear

• The middle ear is where sounds are carried into the deeper parts of the ear. The middle ear is comprised of three bones, called the "ossicles." They are some of the smallest bones in the human body. The bones are the malleus, or hammer; incus, or anvil; and stapes, or stirrup. The bones are so named because of their shape. The middle ear transmits the sounds into smaller and stronger vibrations. On the inner end of the middle ear is the eustacian tube, which connects the middle ear to the back of the throat.
  
  

Labyrinth

• The most inner part of the ear is the labyrinth, which also is called the "vestibular apparatus." The labyrinth is aptly named because it has three canals and a vestibule. (It also contains the cochlea, which is discussed later.) The fluid filling the labyrinth is called "perilymph." The three canals are semicircular, and the vestibule is where the canals join. The canals and the vestibule are mostly concerned with keeping a person's balance. It works with a person's vision to keep objects in focus when his head is moving.
  
  

Cochlea

• From the middle ear, vibrations continue to travel further into the inner ear, which houses the cochlea, the auditory part of the inner ear. The cochlea is a coiled tube that has bony walls. It is about 3.5 cm long and about 2 mm in diameter. The cochlea is a fluid-filled cavity. The fluid is mostly water. The watery fluid moves when vibrations come from the middle ear through the inner ear. When the fluid moves, special cells change the motion to signals, which auditory nerve cells pick up and eventually send to the brain.