Vibrations of the stapes at the Vestibular nerve oval window induces fluid Auditory nerve pressure waves in the cochlea fluids Oval Cross section of cochlea window Round Scala Tectorial media window Cochlea membrane Scala vestibuli Spiral lio this pi Scala tympani Inner hair cells Outer membrane
Vibrations of the stapes at the oval window induces fluid pressure waves in the cochlea fluids. QuickTime™ and a Animation decompressor are needed to see this picture
Sound waves enter the scala vestibuli, pass through the scala media at some point in their course to the scala tympani and round window, oscillating the basilar membrane QuickTime and leede m tensor tympan m stapedius Vestibule Oval window Scala media of malleus ess of incus Helicotrema membranc ,· Cochlear partition stapedial joint 2.crus stapes Scala tympani footplate Round window Eustachian tube
Sound waves enter the scala vestibuli, pass through the scala media at some point in their course to the scala tympani and round window, oscillating the basilar membrane. QuickTime™ and a Animation decompressor are needed to see this picture
Pressure waves in the scala vestibuli are conducted through ( bi Direction of wave propagation the scala media and into the scala tympani at the point of maximum deflection of the basilar membrane. This sets up a traveling wave in the basilar Base: Basilar membrane membrane, high frequency at the is narrow and stiff Apex base, low frequency at the apex BM is wide and compliant Relative 1600Hz Basilar membrane 800H Scala vestibuli Cochlear base 200Hz 100Hz Scala mani Unrolled Tympanic Narrow base of Distance from membrane basilar membrane Wider apex is Cochlear Helicotrema stapes(mn Stapes on is"tuned"for high,"tuned"for apex oval window frequencies low frequencies Thus the basilar membrane is tonotopically organized
Pressure waves in the scala vestibuli are conducted through the scala media and into the scala tympani at the point of maximum deflection of the basilar membrane. This sets up a traveling wave in the basilar membrane, high frequency at the base, low frequency at the apex. Apex: BM is wide and compliant Base: Basilar membrane is narrow and stiff Thus the basilar membrane is tonotopically organized
Traveling W ave behavior of QuickTime and a are needed to see this picture the basilar membrane The traveling wave appears to move to the right(cochlear apex This is an illusion. High frequencies vibrate more frequently higher amplitudes, thus displacement of the basilar h over time than low frequencies, while low frequencies lave membrane in response to a single click(broadband noise) “ appears”" to move to the right
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In order to sense the oscillations of the basilar membrane. we must introduce a sensory receptor, the hair cell