The membranous labyrinth is filled with which fluid?

The membranous labyrinth is filled with which fluid?

• A. Perilymph
• B. Water
• C. Endolymph
• D. Air

Answer: (C)

Endolymph fills the membranous labyrinth. This fluid is specialized for the inner ear, with a high potassium concentration that helps create the endocochlear potential, a key driver for hair cell transduction. When the head moves, endolymph flow deflects hair cell stereocilia, generating neural signals that encode balance and spatial orientation. The surrounding bony labyrinth, by contrast, is filled with perilymph, not inside the membranous structure. Water or air are not the fluids that populate the membranous labyrinth.

Endolymph fills the membranous labyrinth. This fluid is specialized for the inner ear, with a high potassium concentration that helps create the endocochlear potential, a key driver for hair cell transduction. When the head moves, endolymph flow deflects hair cell stereocilia, generating neural signals that encode balance and spatial orientation. The surrounding bony labyrinth, by contrast, is filled with perilymph, not inside the membranous structure. Water or air are not the fluids that populate the membranous labyrinth.