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 organizedPressure 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