Exercise 9. Complete this description using the words and phrases below:
pinna
inner ear
ear canal
oval window
eardrum
cochlea
sound waves
hair cells
middle ear
auditory nerve
How the Ear Works
Sounds from the outside world are picked up by the outer ear, which is made up of the … (1) and the ear canal. As the sound waves enter the ear, the … (2) serves to increase the loudness of those pitches that make it easier to understand speech. At the same time the ear canal protects another important part of the ear: the … (3) - a flexible, circular membrane which vibrates when touched by … (4). The sound vibrations continue their journey into the … (5), which contains three tiny bones called the ossicles, which are also known as the hammer, anvil and stirrup. These bones form the bridge from the eardrum into the … (6). They increase and amplify the sound vibrations even more, before safely transmitting them on to the inner ear via the … (7).
The inner ear, or … (8), resembles the circular shell of a snail, and houses a system of tubes which are filled with a watery fluid. As the sound waves pass through the oval window the fluid begins to move, setting tiny … (9) in motion. In turn, these hairs transform the vibrations into electrical impulses that travel along the … (10) to the brain itself.
Exactly how the brain actually translates these nerve impulses remains a mystery.