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How do otoliths stimulate hair cells involved in balance?

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Diagram showing auditory mechanisms in insects, including labeled illustrations of a scolophore organ, the mosquito ear with antenna shaft and scolophores, the cicada ear with auditory capsule and tympanic membrane, and the grasshopper ear with sensory body and tympanic membrane. — sound reception Auditory mechanisms in insects. (Left) A scolophore organ. (Top right) The mosquito ear. (Centre right) The ear of the cicada *Magicicada septendecim*. (Bottom right) The ear of the grasshopper.

Otoliths, also known as otoconia or statoconia, are dense calcium carbonate crystals embedded in the gelatinous otolithic membrane that covers the sensory macula within the utricle and saccule.12

Because these crystals are significantly denser than the surrounding endolymph and membrane, they possess greater mass, which makes them highly sensitive to gravitational forces and linear acceleration. When the head tilts or moves, the inertia of the dense otoliths causes the otolithic membrane to shift relative to the underlying sensory epithelium.134

This movement creates a parallel, or shearing, force that deflects the hair bundles—consisting of stereocilia and a kinocilium—projecting from the hair cells. This mechanical deflection stimulates the hair cells to alter the rate of nerve impulses sent to the brain via the vestibulocochlear nerve, allowing the body to perceive its position relative to gravity and detect linear motion.1423