Anatomy of human ear II. – How work hair cells

Although I am no scientist, I can understand basic principle of hair cells functioning. They are cells of special type and their purpose is to transform mechanic sound waves of acoustic pressure into electrical signals, which is send through Cochlear nerve into hearing centre of brain. On the surface of hair cells there are hair-like projections – stereocilia. Stereocilia are stimulated by incoming sound wave and start to vibrate (they are bending back and forth), and that leads to generating electrical impulses through changes within the hair cells.
Because of aging, hair cells are losing stereocilia and with them also sensitivity to sound – that is natural process. But that could happen also in one moment when one is exposed to acoustic trauma.

Video on functioning of stereocilia in laboratory conditions:



Keep in mind:

One must always keep in his mind, that heavily damaged hair cells die and are replaced with so called support cells. Human hair cells, in contrast with birds, fishes or reptiles, does not regenerate naturally, and up until now there is no known way to regenerate or to stimulate growth of new hair cells medically. Therefore one has to constantly take care about own ears, especially while visiting discotheques, night clubs, music concerts, shooting ranges, fireworks, motorcycles... etc.

More detailed information about hair cells:
http://www.ncbi.nlm.nih.gov/books/NBK10867/