The membranous labyrinth is a complex system of fluid-filled sacs and tubes located within the inner ear. It is part of the inner ear and is responsible for the senses of hearing and balance. The membranous labyrinth contains structures such as the cochlea, vestibule, and semicircular canals, which play crucial roles in processing sound and maintaining equilibrium. This labyrinth is surrounded by the bony labyrinth, which is a rigid outer structure. The space between the membranous and bony labyrinth is filled with a fluid called perilymph, while the inside of the membranous labyrinth contains another fluid known as endolymph. Together, these fluids help transmit sound vibrations and detect changes in head position.