The Outer Ear
The pinna (1) funnels sound waves down the auditory canal (2) towards the tympanic membrane (3).
The curves and ridges of the pinna serve to filter the sound so that we can determine the direction it is coming from, while the cupped shapeaids our ability to focus on sound to the front.
The Middle Ear
The middle ear is a small air-filled space behind the eardrum. In this area, you find three small bones - the malleus (hammer), incus (anvil) and stapes (stirrup) - known as the ossicles (4). Their purpose is to transfer the vibration of the eardrum to the inner ear.
The middle ear is connected to the throat by the Eustachian tube (5), which opens when you yawn or swallow to equalise the cavity air pressure with the environment.
The Inner Ear
The inner ear is comprised of the cochlea (6) and vestibular organs (7).
The cochlea is a fluid filled spiral which houses thousands of delicate hair cells that convert vibration/sound energy into electrical impulses. These travel to the brain along the auditory nerve, where they are perceived as sound.
The vestibular system consists of the semicircular canals and otolith organs that detect movement and orientation of the head. This information is used to keep our vision steady and maintain our balance as we move around.