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How do the utricle and saccule help vertebrates detect gravity?

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Meissner's corpuscle; mechanoreception — Mechanoreception In human skin, specialized nerve endings known as Meissner's corpuscles (or tactile corpuscles) are sensitive to touch. They are one of several different types of mechanoreceptors found in human skin.

The utricle and saccule, known as otolith organs, function as gravity receptors by detecting linear acceleration and the position of the head relative to the vertical.12

Each organ contains a sensory patch called a macula, which consists of hair cells topped by bundles of cilia. These hair cells are covered by a gelatinous otolithic membrane embedded with dense, calcium carbonate crystals called otoliths (or otoconia). Because these crystals are significantly denser than the surrounding fluid, gravity exerts a constant force on them.13

When the head tilts or undergoes linear acceleration, the weight of the otoliths causes the membrane to shift, creating a shearing force that deflects the cilia. This mechanical displacement stimulates the hair cells to alter the rate of nerve impulses sent to the brain. While the utricle’s macula is primarily oriented horizontally and the saccule’s is oriented vertically, both organs work together to provide the brain with essential information regarding the body's postural equilibrium and orientation in space.1432