The cochlea is a snail shaped, spiral tube in the inner ear that is filled with a liquid called perilymph, which is similar in composition to spinal fluid. If the cochlea was uncoiled it would measure only 30mm in length, which is only 1.181 inches. This tiny structure has a giant job to perform. The cochlea contains thousands of hair cells which are responsible for our balance and hearing. The cells, that resemble human hair, detect sound vibrations in the perilymph and convert this data into electric signals that are sent to the auditory portion of the brain. Once damaged, hair cells, in mammals do not repair themselves or regenerate.
Archive for April, 2012
Otosclerosis is the most frequent cause of middle ear hearing loss for people between the ages of 15 and 35, typically starting at age 20. It is a disease of the middle ear that causes an abnormal, sponge-like, bone growth on the stapes. The stapes is the smallest bone in the human body! It is the tiny stirrup-shaped bone in the middle ear that vibrates and moves in response to sound waves. The cause of otosclerosis is unknown, though it is considered to be genetic because approximately 60% of all cases run in families. This disease is rare in African Americans and less common in people of South American and Japanese decent. Approximately 10% of the Caucasian population in America is affected. It occurs twice as often in women than men.
Meniere’s disease, also known as idiopathic endolymphatic hydrops, is considered a chronic disorder of the inner ear. House and Grey’s Anatomy fans may know that Idiopathic is an adjective that means arising spontaneously or from an unknown cause. Endolymph is the fluid contained in the membranous labyrinth. The receptors of hearing and equilibrium are housed in the membranous labyrinth which is a collection of fluid filled tubes and chambers located in the inner ear. Hydrops refers to the pressure or fullness in the ears. The cause is unknown and usually begins between the ages of twenty and fifty. Studies have shown that it affects two out of every one thousand people, similar to the statics for Multiple Sclerosis. Men and women are equally affected and in most cases only one ear is involved.