Final answer:
The gel-like membrane overlying the hair cells of the spiral organ of Corti is called the tectorial membrane. It plays a crucial role in the transduction of sound waves.
Step-by-step explanation:
The gel-like membrane overlying the hair cells of the spiral organ of Corti is called the tectorial membrane. It is attached to the organ of Corti and plays a crucial role in the transduction of sound waves into nerve impulses. The stereocilia of the hair cells extend into small dimples on the lower surface of the tectorial membrane, and when the membrane slides across them, it bends the stereocilia towards or away from the tallest member of each array. This bending stimulates the hair cells to depolarize and trigger nerve impulses that are transmitted to the cochlear nerve.