cochlear fluid

The cochlea, a spiral-shaped cavity in the inner ear, contains two fluid-filled labyrinths: the bony labyrinth and the membranous labyrinth. The bony labyrinth is filled with perilymph, a fluid similar to cerebrospinal fluid, while the membranous labyrinth contains endolymph, a fluid unique for its high potassium and low sodium ion concentration. These fluids do not mix. The cochlea's primary function is hearing, housing the organ of Corti, which contains hair cells that convert sound vibrations into nerve impulses sent to the brain.123