Sense of balance

The sense of balance comes from the vestibular system, a set of inner ear structures and nerve pathways that registers which way the head is facing and when it accelerates.

Inside the inner ear there is a fluid called endolymph. When the head moves, that fluid accelerates, and as it shifts it bends tiny hairs called stereocilia that stick out from the hair cells, the sensory cells of balance. Moving fluid bends tiny hairs, and that bend is the signal. Bending to one side depolarizes the hair cells, meaning it changes their electrical charge and makes them fire off a message.

That message travels along the vestibular nerve and reaches the vestibular nuclear complex, a group of nuclei in the brainstem, the lower part of the brain that connects to the spinal cord. From there, eye movements and posture are adjusted, and that is why your gaze stays steady while you walk.