The Ear Essay, Research Paper

THE EAR

The Ear is one of the five sense organs. It allows us to hear. Hearing is one of our most important senses. Speech development depends on hearing. Without hearing, our speech would not sound right. Children learn to talk by copying what other people say. Hearing is not a simple process. Movement causes sounds, so there are lots of things to hear. Sounds travel in waves. The waves enter the ear, and the brain interprets the sound signals as sounds.

Surprisingly, the ear also helps us balance.

There are three main parts of the ear. The three parts are the outer ear, middle ear, and sure enough, the inner ear. The outer ear is made up of two main parts. The two parts are the auricle and the external auditory canal. The auricle is the part of the ear you see on people. It is fleshy, and contains no bones. The loosely hanging part of the auricle is the earlobe. It is made up of fat. Three muscles attach the auricle to the head. They are small, and serve no purpose in humans. However, some people can move and wiggle their ears. Many animals can also do this to improve their hearing. Some of the animals are cats, dogs, foxes, horses and rabbits. The external auditory canal is the part you see when you look straight into the ear. The external auditory canal is about and inch long. To stop dirt from getting onto the eardrum (or timpanic membrane), the outer third of the eardrum has hairs, sweat glands, and glands that produce earwax. The inner two thirds of the ear is surrounded by the hardest bone in you body, the temporal bone. It also surrounds the middle and inner part of the ear. The temporal bone protects delicate structures in the ear.

The middle ear starts behind the timpanic membrane. The three bones called the ossicles are part of the middle ear. The three bones are the malleus, which means hammer, incus, which means anvil, and stapes, which means stirrup. The largest of the three is the malleus. One end of the malleus is connected to the incus; the other is connected to the timpanic membrane. The incus connects the malleus to the stapes. The stapes is the smallest bone in the body. The footplate of the stapes is connected to the oval window, a membrane. Another part of the middle ear is the Eustachian tube. It is connected to the throat and allows air to pass between the two.

The inner ear is very delicate. It is sometimes called the labyrinth. The inner ear has three main parts, which are all connected. The three parts are the vestibule, the semicircular canals, and the cochlea. The vestibule is a round chamber about 5 millimeters long. It connects the semi-circular canals to the cochlea. There are two sacs with a swelling inside the vestibule with hair lining them. The sacs are called the utricle and saccule. There are three semi-circular canals. Each has a fluid filled tube or duct. One end of each of the semi-circular canals forms a pouch with hair cells attached to nerve fibers. The cochlea is in front of the vestibule. It is shaped like a snail. Fluid filled ducts go through the cochlea. One wall of the cochlea is the basilar membrane. It has over 15000 hairs, which make up the corti, the actual organ of hearing.

Hearing is a very complex process. First, the auricle collects sound waves. Then, then sound waves travel through the external auditory canal and strike the timpanic membrane. The timpanic membrane vibrates, and the vibrations of it cause the malleus to vibrate. The malleus then makes the incus vibrate and the incus causes the stapes to vibrate. The ossicles amplify the sound. The footplate of the stapes vibrates within the oval window. These movements create waves in the fluid in the cochlea. The sounds reach the brain by tiny hairs in the cochlea moving to create messages in the nerves deep in the inner ear. The messages then go to the brain, and are identified as sounds or music.