Audiology, Hearing Aids, Hearing Loss

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Hearing and The Ear

Hearing is an intricate and beautiful process. While this is a simplified definition, it should help explain how the human body hears.

Parts of the Ear

There is the outer ear -the pinna (what we call the ‘ear’, the cartilaginous flap that can contain an earring (or earrings) and the ear canal.

Second, the middle ear - the tympanic membrane [ear drum], the ossicular chain [the three little bones known as the malleus, incus and stapes] and the Eustachian tube [this tube keeps the pressure inside the middle ear equal with the outside pressure, and is what is responsible for the ‘popping’ sensation when yawning or chewing during a change in altitude].

Third, the inner ear which contains the cochlea [snail like organ of hearing] and the VIII nerve [hearing nerve].

How We Hear

Hearing starts when incoming sound travels as vibrations through the air which are directed into the ear canal. The sound hits the eardrum causing it to move back and forth. Attached to the eardrum are three small bones known as the hammer, anvil and stirrup (malleus, incus and stapes). The stirrup moves in and out of an opening known as the oval window contained in the snail-like organ called the cochlea. Inside the cochlea are fluid and thousands of hair-cells. Movement of the fluid causes the hair cells to bend and send a signal to the neurons (the building blocks of nerves) attached to the hair cells. These neurons send the signal to the VIII nerve (hearing nerve) which travels up to the higher centers in the brain. The brain in turn interprets the type of sound perceived, so you can tell if you are hearing the telephone, loved one calling you, etc.