The inner ear is a tiny but notable body part; not only is it important to hearing, but it is also where the balance organs and nerves are located.
The basic components of the inner ear include semicircular canals, the cochlea, the utricle, the saccule, and the vestibulocochlear nerve. The cochlea and one half of the vestibulocochlear nerve (the cochlear nerve) are responsible for hearing. The remaining semicircular canals, utricle, saccule, and vestibular nerve are responsible for balance.
There are three semicircular canals that contain fluid to activate sensory hair cells, which are arranged at 90-degree angles and detect different kinds of movement:
Up and down
Side to side
The utricle connects the semicircular canals to the saccule, which also detect motion. They are located in the vestibule inside of the labyrinth, which is the bony outer wall of the inner ear. All of this is the vestibular system.
But it is not only the vestibular system that assists with balance. Vision and sensory receptors (muscles, joints, skin, etc.) all transmit messages to the brain that work together and voila! balance.