In the cochlear apparatus, which structure directly dissipates energy from the traveling wave?

In the cochlear apparatus, which structure directly dissipates energy from the traveling wave?

• A. Round window
• B. Spiral ganglion
• C. Stria vascularis
• D. Modiolus

Answer: (A)

The traveling wave’s energy is dissipated by the round window. As the basilar membrane vibrates in response to sound, the pressure waves travel through the cochlear fluids. The round window membrane moves in opposition to the oval window, providing a flexible outlet for fluid displacement. This pressure release prevents buildup and helps convert the hydraulic energy of the wave into motion of the round window membrane, effectively damping the energy as the wave travels. The other structures aren’t responsible for directly dissipating this energy: the spiral ganglion houses the auditory nerve cell bodies, the stria vascularis maintains the endocochlear potential and ionic composition, and the modiolus is the central bony core housing nerve fibers—each plays a different role in hearing, not in dissipating the traveling wave energy.

The traveling wave’s energy is dissipated by the round window. As the basilar membrane vibrates in response to sound, the pressure waves travel through the cochlear fluids. The round window membrane moves in opposition to the oval window, providing a flexible outlet for fluid displacement. This pressure release prevents buildup and helps convert the hydraulic energy of the wave into motion of the round window membrane, effectively damping the energy as the wave travels. The other structures aren’t responsible for directly dissipating this energy: the spiral ganglion houses the auditory nerve cell bodies, the stria vascularis maintains the endocochlear potential and ionic composition, and the modiolus is the central bony core housing nerve fibers—each plays a different role in hearing, not in dissipating the traveling wave energy.