Which structure dissipates the energy of the traveling wave within the cochlea?

• A. Basilar membrane
• B. Tectorial membrane
• C. Round window
• D. Stria vascularis

Answer: (C)

The energy of the traveling wave in the cochlea is dissipated by the round window, which acts as a pressure-release boundary for the cochlear fluids. When the stapes pushes on the oval window, the incompressible perilymph needs an outlet, so the round window membrane moves outward in opposition to the oval window. This movement allows fluid displacement and dampens the traveling wave energy, converting mechanical energy into heat within the surrounding tissues and fluids. The basilar membrane is where the traveling wave is translated into local displacements that encode frequency, the tectorial membrane participates in hair-cell stimulation, and the stria vascularis maintains ionic composition of the endolymph—none of these primarily dissipate the wave’s energy.