Which structure helps terminate pressure waves by allowing fluid displacement?

Which structure helps terminate pressure waves by allowing fluid displacement?

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

Answer: (A)

When sound creates pressure waves inside the cochlear fluids, the fluid is nearly incompressible, so there must be a flexible outlet to relieve that pressure. The round window membrane serves this role, bulging outward as the stapes pushes on the oval window, allowing fluid to move and preventing pressure buildup. This termination of the pressure wave lets the wave propagate properly through the cochlea without reflecting back. The basilar membrane, by contrast, is where the fluid wave causes hair cells to bend and transduce mechanical energy into neural signals. The spiral ganglion contains the auditory nerve cell bodies, and the stria vascularis maintains the ionic composition of endolymph. These structures aren’t responsible for terminating pressure waves.

When sound creates pressure waves inside the cochlear fluids, the fluid is nearly incompressible, so there must be a flexible outlet to relieve that pressure. The round window membrane serves this role, bulging outward as the stapes pushes on the oval window, allowing fluid to move and preventing pressure buildup. This termination of the pressure wave lets the wave propagate properly through the cochlea without reflecting back. The basilar membrane, by contrast, is where the fluid wave causes hair cells to bend and transduce mechanical energy into neural signals. The spiral ganglion contains the auditory nerve cell bodies, and the stria vascularis maintains the ionic composition of endolymph. These structures aren’t responsible for terminating pressure waves.