I don’t really know how our ears actually work – so I had to research it so that I could tell Mum. Here is a brief summary of how the ears function.
Our ears are made up of three sections called the outer ear, middle and inner ear, with each section serving its own purpose in the detection and interpretation of sound.
Sounds reach our ears as sound waves and the function of the outer ear is to concentrate the sound waves by channelling it via the pinna (or auricle). This acts like a funnel to amplify the sound and direct the sound waves into the ear canal, then to the ear drum.
The ear canal and middle ear are separated by the oval shaped ear drum, which is made up of a very thin, semi-transparent membrane, approximately 1cm in diameter. When sound waves hit the ear drum, it vibrates and transfers these vibrations on to three small bones in the middle ear called ossicles. These three bones are called hammer (malleus), anvil (incus) and stirrup (stapes). The middle ear section is filled with air and almost sealed, as a result to equalise the internal pressure with the outside, the Eustachian tube exists and is connected to the throat, to drain fluid.
As the three small bones vibrate, they amplify the vibrations into the inner ear to arrive at a coiled structure called the cochlea, which is lined with hair cells. Fluid in the cochlea begins to move and the vibrations are picked up by the sensory hair cells. These then send electrical signals via the auditory nerve to the brain, which then interprets them as sound.