The inner ear is called a labyrinth. The labyrinth itself is comprised of a bone shell known as the bony labyrinth, which is designed to offer protection for the membranous labyrinth it encompasses. There is a space in between theses two labyrinths which is filled with fluid known as perilymph.
Perilymph is a secreted fluid, constantly supplied by the cells which line the bony canal. A second fluid can be found within the structure of the tubular maze inside the membranous labyrinth. This fluid is known as endolymph. Both fluids are equipped to help discern vibrations to assist in the process of hearing as well as help the body maintain a sense of balance and equilibrium.
There are three structural cavities within the bony labyrinth, the vestibule, the semicircular canals, and the cochlea. The necessary organs for hearing and maintaining balance are embedded and supported within these three regions.