What is the name of the membrane that separates the scala media and the scala vestibuli?

The membrane that separates the scala media and the scala vestibuli is known as Reissner's Membrane. This structure is essential in the anatomy of the cochlea, which is part of the inner ear. Reissner's Membrane helps to create a distinct separation between the two fluid-filled compartments, thereby playing a crucial role in the function of the cochlea. It allows for the establishment of electrochemical gradients necessary for transducing sound waves into nerve impulses, which are then sent to the brain for auditory processing.

In contrast, other structures listed, such as the Basilar Membrane, help separate the scala media from the scala tympani and are involved in the function of the hair cells that detect sound. The Oval Window and the Round Window serve as interfaces between the inner ear and the middle ear, facilitating the movement of fluid within the cochlea but are not involved in separating the scala media from the scala vestibuli. Thus, Reissner's Membrane is the correct answer, highlighting its vital role in the auditory system's anatomy and function.