The Human Ear
What did the person say? Please speak louder? Without ears on the side of the head people would not be able to hear their name, the sound of a phone ringing, or music. The human ear, though, is not just for hearing; it also helps with balance. There are three main parts of the ear, with each of them having a shared responsibility: outer ear, middle ear, and inner ear.
The outer ear is the part that can be seen in the mirror, scratched, or cleaned behind. The ear is also called the pinna. The ear is made of cartilage covered by skin, which has a part called the ear lobe, the place where some people attach earrings. The outer ear contains the ear canal, which is similar to a canal for water, but this canal is a pathway for all the sounds in the environment to enter. The lining of the canal is the place earwax is produced. The earwax helps keep the eardrum from drying out as well as trapping any dirt before it gets to the eardrum. If this happens it can cause an infection. The outer ear catches the sound waves and funnels them to the eardrum, where the middle ear is located.
The middle ear is basically air-filled space located inside the eardrum. For proper hearing, the pressure placed on both sides of the eardrum must be equal. If the pressure is not equal, a person's ears may pop, like what happens on an airplane or at the swimming pool.
The Eustachian tube connects the middle ear to the back of the nose and helps keep the pressure equal. There are three bones inside the eardrum called ossicles (it rhymes with popsicles). The bones are very tiny and include the hammer (malleus), anvil (incus), and stirrup (stapes). The names of each of these bones match what they look like, and the stirrup is the smallest bone of the entire human body. Once sound waves enter the eardrum, these bones pass along the vibrations to the cochlea.
The cochlea are tiny organs located inside the third part of the ear, the inner ear. The cochlea is shaped like a shell and takes the vibrations from the middle ear and changes them into nerve impulses traveling to the brain along the auditory nerve. The brain interprets the sound and sends the information to you.
Also located inside the inner ear are semicircular canals. These are tubes that help a person balance their body. They are filled with a fluid and lined with tiny hairs. As a person moves around, the fluid moves, and the tiny hairs sends impulses to the brain helping them maintain their balance. When a person spins in a circle too quickly, the fluid is still moving when they stop, but the brain thinks the person is still moving, causing them to lose balance.
Everything that makes a sound creates sound waves, and the change in the air pressure caused by the sound waves is what ultimately allows a person to hear and interpret sounds every day. If someone was simply moving their lips, there are no sound waves, no pressure, so there would be nothing to hear. This is why in space, the sounds between astronauts cannot be heard because there is no air. They must use special equipment to hear each other. Air must be present for a sound to be made and then heard by another person.
Finally, it is important to take care of the ears just like the rest of the body. Sticking anything into the ear, playing the volume too loud while listening to music or playing a video game can be harmful to the ears. It can cause damage to the eardrum now and in the future.
In summary, the human ear is an important organ of the body containing three main parts; the outer ear, the middle ear, and the inner ear. They all work together to give people the ability to hear.