Division of Balance and senses

Balance (Equilibrium)
Balance can be divided into two senses: dynamic equilib­rium, requiring a knowledge of angular and/or rotational movement, and static equilibrium, requiring a knowledge of movement in one place, either vertical or horizontal.
Dynamic equilibrium is required when the body is moving. During movement, the fluid within the semicircular canals flows over and displaces the gelatinous cupula within the ampullae. This causes the cilia of the hair cells to bend and to initiate nerve impulses that travel to the brain. Continuous movement of the fluid in the semicircu­lar canals causes one form of motion sickness.
When the body is still, the otoliths in the utricle and the saccule rest on the otolithic membrane above the hair cells. Static equilibrium is required when the body moves horizontally or vertically. At that time, the otoliths are displaced, and the otolithic membrane sags, bending the cilia of the hair cells beneath it. The hair cells then generate nerve impulses that travel to the brain via the vestibular branch of the vestibulocochlear nerve.
Movement of fluid within the semicircular canals contributes to the sense of dynamic equilibrium. Movement of the otoliths within the utricle and the saccule is important for static equilibrium.