Britannica
Sources used in this answer
- human ear - The physiology of balance: vestibular function
- human nervous system - Vestibulo-ocular reflex
- human ear - Detection of angular acceleration: dynamic equilibrium
- Movement perception - Vestibular system
- audiology - Vestibular assessment
- human ear - Disturbances of the vestibular system
- human ear - Detection of linear acceleration: static equilibrium
- human nervous system - Saccule and utricle
How does the vestibular system help the body sense balance and motion?
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audiology
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The vestibular system, located within the inner ear, is the primary sensory apparatus responsible for maintaining postural equilibrium and sensing motion. It functions through two distinct sets of specialized organs that detect different types of acceleration:12
- Semicircular Canals: These three fluid-filled canals are oriented at right angles to one another, allowing them to function as a rotary accelerometer. When the head rotates, the inertia of the internal fluid (endolymph) causes it to lag, deflecting a jellylike structure called the cupula. This movement bends sensory hair cells, which transmit nerve impulses to the brain regarding angular acceleration.32
- Utricle and Saccule: Located within the vestibule, these organs detect linear acceleration and changes in head position relative to gravity. They contain otoliths—tiny crystals that shift in response to movement—which exert pressure on hair cells to signal changes in position.1425
This information is processed by the brain to coordinate eye movements (the vestibulo-ocular reflex) and adjust muscle tone in the trunk and limbs to maintain balance.62