The otolithic membrane is covered in crystals made of which mineral?

The otolithic membrane is covered in crystals made of which mineral?

• A. Silicon dioxide
• B. Sodium chloride
• C. Magnesium sulfate
• D. Calcium carbonate

Answer: (D)

The otolithic membrane in the vestibular maculae carries tiny crystals called otoconia, and these crystals are made of calcium carbonate. Their weight provides a slight inertia to the membrane so that, when the head tilts or the body accelerates linearly, the otoconia shift relative to the gelatinous layer and bend the hair cell bundles. This bending of the stereocilia triggers receptor potentials that inform you about gravity and linear motion. The other minerals listed don’t form otoconia, so calcium carbonate is the correct choice.

The otolithic membrane in the vestibular maculae carries tiny crystals called otoconia, and these crystals are made of calcium carbonate. Their weight provides a slight inertia to the membrane so that, when the head tilts or the body accelerates linearly, the otoconia shift relative to the gelatinous layer and bend the hair cell bundles. This bending of the stereocilia triggers receptor potentials that inform you about gravity and linear motion. The other minerals listed don’t form otoconia, so calcium carbonate is the correct choice.