FREE ESSAY ON THE HUMAN BRAIN

THE HUMAN BRAIN

THE HUMAN BRAIN
The human body is divided into many different parts called organs. All of the parts are
controlled by an organ called the brain, which is located in the head. The brain weighs
about 2.75 pounds, and has a whitish-pink appearance. The brain is made up of many cells,
and is the control center of the body. The brain flashes messages out to all the other
parts of the body. The messages travel in very fine threads called nerves. The nerves and
the brain make up a system somewhat like telephone poles carrying wires across the city.
This is called the nervous system. The nerves in the body don't just send messages from
the brain to the organs, but also send messages from the eyes, ears, skin and other
organs back to your brain. Some nerves are linked directly to the brain. Others have to
reach the brain through a sort of power line down the back, called the spinal cord. The
brain and spinal cord make up the central nervous system. The brain doesn't just control
your organs, but also can think and remember. That part of the brain is called the mind.

Twenty-eight bones make up the skull. Eight of these bones are interlocking plates. These
plates form the cranium. The cranium provides maximum protection with minimum weight, the
ideal combination. The other twenty bones make up the face, jaw and other parts of the
skull. Another way the brain keeps it self safe is by keeping itself in liquid. Nearly
one fifth of the blood pumped by the heart is sent to the brain. The brain then sends the
blood through an intricate network of blood vessels to where the blood is needed.
Specialized blood vessels called choroid plexuses produce a protective cerebrospinal
fluid. This fluid is what the brain literally floats in. A third protective measure taken
by the brain is called the blood brain barrier. This barrier consists of a network of
unique capillaries. These capillaries are filters for harmful chemicals carried by the
blood, but do allow oxygen, water and glucose to enter the brain. 
The brain is divided into three main sections. The area at the front of the brain is the
largest. Most of it is known as the cerebrum. It controls all of the movements that you
have to think about, thought and memory. The cerebrum is split in two different sections,
the right half and the left half. The outer layer of the cerebrum is called the cortex.
It is mainly made up of cell bodies of neurons called grey matter. Most of the work the
brain does is done in the cortex. It is very wrinkled and has many folds. The wrinkles
and folds give the cortex a large surface area, even though it is squeezed up to fit in
the skull. The extra surface area gives the cerebrum more area to work. Inside the
cortex, the cerebrum is largely made up of white matter. White matter is tissue made only
of nerve fibres. The middle region is deep inside the brain. It's chief purpose is to
connect the front and the back of the brain together. The back area of the brain is
divided into three different parts. The cerebellum sees to it that all the parts of your
body work as a team. It also makes sure you keep your balance. The thalamus is located in
between above the lower brain and under the two hemispheres.
THE DIFFERENT SECTIONS OF THE BRAIN: Most of the above mentioned parts of the brain were
produced early in evolution but the higher mammals, especially humans went on to produce
a sort of thinking cap on top of these parts. This thinking cap was divided into two
different parts, the left hemisphere and the right hemisphere. If the left side of your
brain is more developed like most people's are, you are right handed. On the other hand
if the right side of your brain is more developed, then you will be left handed. The
right side of your brain is more artistic and emotional while the left side of your brain
is your common sense and practical side, such as figuring out math and logic problems. 
THE CEREBELLUM: One of the most important parts of the human brain is the cerebellum. The
cerebellum is involved with the more complex functions of the brain and sometimes is even
referred to as the brain within the brain. The cerebellum acts as a control and
coordination center for movement. The cerebellum carries small programs that have been
previously learned. For example, how to write, move, run and jump are all previously
learned activities that the brain recorded and can playback when needed. Every time you
practice, the brain rewrites the program and makes it better. You may have heard the
saying practice makes perfect. Well this saying is not entirely true; another way of
practicing is just to imagine what you wish to do. Since the cerebellum can't actually
feel, it will think that you are doing what your imagining and respond by rewriting it's
previous program and carrying out any other actions needed for that function. 
THE CEREBRAL CORTEX: The cerebral cortex makes up the top of the two hemispheres of the
brain. The cortex is a sheet of greyish matter which produces our thoughts, language and
plans. It also controls our sensations and voluntary movements, stores our memories and
gives us the ability to imagine, in short it's what makes humans, humans. 
BIBLIOGRAPHY. 
The Internet, various sites.
Microsoft Encarta Encyclopedia 1998 edition 
Britannica by Britannica, Encyclopedia Inc.copyright Encyclopedia Britannica Inc., 19864.