The inner ear is the deepest part of the whole ear, and is located in a place known as the bony labyrinth, which is a maze of bone passageways lined by a network of fleshy tubes known as the membranous labyrinth. A cushion of fluid, called perilymph, lies between the bony and membranous labyrinth, while a fluid called endolymph is found within the membranous labyrinth itself.
The inner ear consists of;
• Cochlea : dedicated to hearing
The cochlea is a bony, spiral-shaped chamber that contains the cochlear duct of the membranous labyrinth. The sense of hearing is provided by receptors within the cochlear duct. A pair of perilymph-filled chambers is found on each side of the duct. The entire apparatus makes turns around a central bony hub, much like a snail shell.
• Vestibular system : dedicated to balance
The vestibule contains a pair of membranous sacs: the saccule (sacculus) and the utricle (utriculus). Receptors in the vestibule provide for sensations of gravity and linear acceleration.
(The inner ear is innervated by the eighth cranial nerve in all vertebrates.)
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