Equilibrioception is the sense of balance. This is what prevents a person or animal from falling over while walking or doing other physical activity.
In humans, equilibrioception is mainly sensed by the detection of acceleration, which occurs in the vestibular system. Other senses play roles as well, e.g. the visual system and proprioception. The importance of visual input for balance is illustrated by its being harder to stand on one foot with eyes closed than with eyes open.
The sense of balance often gets worse as a person ages. After a stroke, it may be improved with the help of special training.
Images for kids
Diagram of vestibular system
This diagram linearly (unless otherwise mentioned) tracks the projections of all known structures that allow for balance and acceleration to their relevant endpoints in the human brain.
Illustration of the flow of fluid in the ear, which in turn causes displacement of the top portion of the hair cells that are embedded in the jelly-like cupula. Also shows the utricle and saccule organs that are responsible for detecting linear acceleration, or movement in a straight line.