The tiny organ in the inner ear whose structures are important components in hearing mechanism is known as the cochlea. The cochlea looks like a curved snail shell and comes from a Latin word that means “snail shell. The tiny hair cells that are located in the cochlea send the impulses from nerve to the auditory nerve which transmits sound information to the brain.
Small hairs called cilia grow in the cochlea’s canals which are filled with fluid. The stapes, the innermost of the three small bones in the ear, inserts into a hole in the cochlea called the oval window. The fluid in the cochlea moves when triggered by movement of the eardrum. Sound travels from the base of the cochlea to the top and causes the cilia to move based on the frequency of the sound. The cilia’s base is connected the auditory nerve which carries information to the brain.
The structure of the cochlea is set up so that certain sounds are processed in different parts of the cochlea. High-pitched sounds are processed in the base and low-pitched sounds are at the top. This distribution of sounds is known as “tonotopic organization.”
Hearing loss can result from damage to the cochlea and the cilia. When damage occurs sound information cannot be changed to nerve impulses that are sent to the brain.
There is a procedure known as a cochlear implant that can restore some function of the cochlea if it is damaged. During an implant an electrode is inserted into the cochlea. The electrode is connected to sensor that takes in sounds. Nerve impulses are then sent to the brain from the implant. A cochlear implant does allow a person to receive some sound but does restore “natural” hearing as the information that is sent to the brain is not as clear as when sent a cochlea.
Fri, Jul 9, 2010
Health