The gelatinous layer bearing otoconia is called which membrane?

• A. Basilar membrane
• B. Otolithic membrane
• C. Tectorial membrane
• D. Endolymphatic membrane

Answer: (B)

In the vestibular system, the gelatinous layer that bears the otoconia is the otolithic membrane. This membrane sits atop the sensory hair cells in the maculae of the utricle and saccule, with tiny calcium carbonate crystals (otoconia) embedded in it. When the head tilts or experiences linear acceleration, the weight of the otoconia shifts the membrane, bending the hair cells and signaling motion to the brain. This mechanism is distinct from the basilar membrane, which supports the organ of Corti in the cochlea for hearing, and from the tectorial membrane, which overlays hair cells in the cochlea. The endolymphatic membrane isn’t the structure that bears otoconia.