Hearing Loss
The mechanism of hearing loss arises from trauma to stereocilia of the cochlea, the principal fluid filled structure of the inner ear. The pinna combined with the middle ear amplifies sound pressure levels by a factor of twenty, so that extremely high sound pressure levels arrive in the cochlea, even from moderate atmospheric sound stimuli. Underlying pathology to the cochlea are reactive oxygen species, which play a significant role in noise-induced necrosis and apoptosis of the stereocilia. Exposure to high levels of noise have differing effects within a given population, and the involvement of reactive oxygen species suggests possible avenues to treat or prevent damage to hearing and related cellular structures.
The elevated sound levels cause trauma to cochlear structure in the inner ear, which gives rise to irreversible hearing loss. A very loud sound in a particular frequency range can damage the cochlea's hair cells that respond to that range thereby reducing the ear's ability to hear those frequencies in the future. However, loud noise in any frequency range has deleterious effects across the entire range of human hearing. The outer ear (visible portion of the human ear) combined with the middle ear amplifies sound levels by a factor of 20 when sound reaches the inner ear.
Read more about this topic: Health Effects From Noise
Famous quotes containing the words hearing and/or loss:
“It is surely a matter of common observation that a man who knows no one thing intimately has no views worth hearing on things in general. The farmer philosophizes in terms of crops, soils, markets, and implements, the mechanic generalizes his experiences of wood and iron, the seaman reaches similar conclusions by his own special road; and if the scholar keeps pace with these it must be by an equally virile productivity.”
—Charles Horton Cooley (1864–1929)
“I have never worked for fame or praise, and shall not feel their loss as I otherwise would. I have never for a moment lost sight of the humble life I was born to, its small environments, and the consequently little right I had to expect much of myself, and shall have the less to censure, or upbraid myself with for the failures I must see myself make.”
—Clara Barton (1821–1912)