Cochlear enhancer
Cochlear amplifier is a technical term for the mechanical amplification of the traveling wave in the cochlea (Latin cochlea ) in the inner ear of mammals, in which the outer cochlear hair cells in the organ of Corti cause frequency-specific movements to adjust dynamics so that very quiet noises can also be perceived. An outer hair cell is therefore also referred to as a motor cell. The gain is not linear - sounds with low SPL are subject to higher gains than those with high SPLs. The failure of the cochlear amplifier leads to hearing loss .
The reinforcement mechanism of the cochlea was described by the German ENT doctor and scientist Hans-Peter Zenner in 1987. For this he was awarded the Gottfried Wilhelm Leibniz Prize of the German Research Foundation.
In the cochlea, sounds and speech are broken down into their individual frequencies , similar to a Fourier analysis . The traveling wave is amplified up to a thousand times by the extremely fast movement of the outer hair cells (auditory cells in the organ of Corti ), which move up to twenty thousand times per second (20,000 Hz ). The hair cells have special motor proteins in order to be able to move. The motor proteins are called prestin (from Italian presto "fast"). In order to modulate the amplification (protection of the inner hair cells from excessive sound intensities), the outer hair cells are also efferent innervated. The fibers originate from the upper olive complex ( nucleus olivaris superior ) and run with the auditory nerve (N. cochlearis, part of the N. vestibulocochlearis = VIII. Cranial nerve ) to the outer hair cells.
Web links
- Voyage au center de l'audition. Retrieved March 16, 2014 (French, English, Spanish, Portuguese, excellent page on the ear, especially on the cochlea).
Individual evidence
- ^ Pape, Hans-Christian 1956-, Kurtz, Armin 1955-, Silbernagl, Stefan 1939-, Klinke, Rainer 1936-2008, Brenner, Bernhard 1950-: Physiology . 9th, completely revised edition. Stuttgart 2019, ISBN 978-3-13-242391-6 .