The utricular and saccular maculae detect linear acceleration and static head tilt. Which feature distinguishes them from the semicircular canal cristae?

• A They contain otoconia (calcium carbonate crystals) embedded in the gelatinous otolithic membrane ✓
• B Their hair cells lack kinocilia and respond only to deflection by otoconial membrane weight
• C They signal angular acceleration of the head in any plane
• D They adapt completely within milliseconds like Pacinian corpuscles

Explanation

Otolith organs carry a heavy otolithic membrane loaded with calcium carbonate otoconia, giving them inertia so they sense sustained linear acceleration, gravity, and static tilt. Semicircular canals have a cupula without otoconia and respond to angular acceleration. Utricular and saccular hair cells still possess kinocilia and stereocilia like all vestibular hair cells, so option B is false, and their responses are tonic and sustained rather than rapidly adapting.

Reference: Ganong Review of Medical Physiology, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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