What separates the outer ear from the middle ear?

The eardrum, also known as the tympanic membrane, serves as a barrier that separates the outer ear from the middle ear. Its primary function is to vibrate in response to sound waves that travel through the air, which then transmits these vibrations to the small bones within the middle ear. This is a crucial step in the hearing process, as it helps convert airborne sound waves into mechanical vibrations that can be interpreted by the inner ear.

The cochlea is part of the inner ear and is involved in converting vibrations into nerve signals for the brain, but it does not serve as a separator between the outer and middle ear. The auditory canal, while it is a part of the outer ear that channels sound waves to the eardrum, does not function as a separator between the two sections. Lastly, the semicircular canals are also located in the inner ear and are involved in balance rather than hearing. Thus, recognizing the role of the eardrum as the separator clarifies its importance in the overall auditory system.