FREE ESSAY ON THE EAR

THE EAR

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.