What membrane separates the scala tympani from the scala media and is the base of the Organ of Corti?

The basilar membrane is the structure that separates the scala tympani from the scala media and forms the base of the Organ of Corti. This membrane plays a crucial role in the process of hearing. When sound waves enter the cochlea, they cause vibrations in the fluid within the scala vestibuli and scala tympani. These vibrations create a traveling wave along the basilar membrane.

The Organ of Corti, which resides on top of the basilar membrane, contains hair cells that act as sensory receptors. When the basilar membrane moves, the hair cells in the Organ of Corti are stimulated, leading to the conversion of sound vibrations into neural signals that the brain interprets as sound.

The other structures mentioned do not serve the same function. Reissner's membrane separates the scala vestibuli from the scala media but does not provide a base for the Organ of Corti. The tympanic membrane, or eardrum, is located in the outer ear and does not have a role in the inner ear structures like the basilar membrane. Similarly, the mastoid membrane is not a recognized component of the cochlear structure related to sound processing. Understanding these anatomical relationships is essential for grasping how sound is processed in the auditory system