Sound waves are amplified by which structure in the ear?

The tympanic membrane, commonly known as the eardrum, plays a crucial role in sound transmission rather than amplification. When sound waves hit the tympanic membrane, it vibrates, converting the sound waves into mechanical energy. This mechanical movement is essential for the propagation of sound waves through the middle ear and onward to the inner ear structures, but it does not amplify the sound.

The structure that primarily amplifies sound in the ear is the stapes. The stapes is one of the three tiny bones in the middle ear, collectively known as the ossicles, which include the malleus, incus, and stapes. As the eardrum vibrates, it causes the malleus to move, which in turn moves the incus, and finally the stapes. The stapes connects to the oval window, a membrane-covered opening to the cochlea.

The amplification occurs because the stapes exerts force on the oval window that is significantly greater than the force exerted by the tympanic membrane, leading to an increase in pressure in the fluid-filled cochlea. This pressure increase is vital for the efficient transmission of sound waves into the inner ear, where they can be processed by the sensory cells.

The cochlea is