What is the function of the tectorial membrane in relation to hair cells?

• A. It overlies the hair cells and participates in mechanotransduction.
• B. It secretes endolymph.
• C. It houses the auditory nerve cell bodies.
• D. It forms the bony labyrinth.

Answer: (A)

The tectorial membrane is a gelatinous layer that sits over the organ of Corti, with the tips of outer hair cell stereocilia embedded in it. When the basilar membrane vibrates in response to sound, the tectorial membrane moves relative to the hair cells, causing a shear deflection of the hair bundles. This bending opens mechanosensitive ion channels on the hair cells, converting mechanical energy into electrical signals that initiate auditory transduction. The membrane itself does not secrete endolymph, house auditory nerve cell bodies, or form the bony labyrinth, so its role is best described as the overlying structure that participates in the mechanical stimulation of hair cells necessary for transduction.