Anatomy of the Human Ear The pinna funnels sound waves into the auditory canal to vibrate the eardrum at a rate that corresponds to the sound’s frequency. In the middle ear, the ossicles pick up the eardrum vibrations, amplify them, and pass them along by vibrating a membrane at the surface of the fluid-filled cochlea in the inner ear. Here fluid carries the wave energy to the auditory receptors that transduce it into electrochemical activity, exciting the neurons that form the auditory nerve, leading to the brain.