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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 centre 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.
PROTECTING THE BRAIN
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 DIFFERENT SECTIONS OF 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. It acts as a "switchboard",
keeping the parts of your brain in touch with each other.
The back area of the brain is divided into three different parts. The pons is
a band of nerve fibres which link the back of the brain to the middle. 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 medulla is low down at the back of your head. It links the brain to the
top of the spinal cord. The medulla controls the way your heart pumps blood
through your body. It also looks after your breathing and helps you digest
food.
THE DIFFERENT PARTS OF THE BRAIN
THE BRAINSTEM: The brainstem is one of the oldest parts of the brain. It
controls such functions as breathing, blood pressure, swallowing and heart
rate.
THE HYPOTHALMUS: This part of the brain is located directly above the brain
stem. The hypothalmus controls basic drives like hunger and sex and as well as
our response to threat and danger. The hypothalmus also controls the
pituitary.
THE PITUITARY: The pituitary produces hormones such as testosterone that
circulate through out the body.
THE THALAMUS: The thalamus is like a relay area; it receives messages from
lower brain areas such as the brainstem and hypothalmus and sends them to the
two brain hemispheres. 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 part 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 centre 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 "practising" 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. This is one why
to explain wet dreams.
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.
IN THE FUTURE
Today many experiments are being conducted that may be break through's for the
future. For instance "brain grafting" is one procedure that may be used in the
future. Brain grafting is to transplant a very thin layer of brain skin from
one person to another. This would result in control of parkinson's disease and
other seizure related diseases.
Another radical idea that has already been successfully been tried on rhesus
monkey's is, brain transplants. The ethics and legal problems for such a
transplant would probably never let this operation be performed on humans.
This is because the person would not be the same, would not have the same
memories or the same abilities that the host body had had.
The last idea of the future that we will list is called "artificial hearing
and seeing". Artificial seeing is achieved by planting sixty-four small
electrodes in front of the visual cortex of the brain. The electrodes are
connected to a small camera that is some where on the person's ear. A computer
is attached to the camera. The computer sends the images from the camera
directly to the implanted electrodes. They flash as the picture from the
camera, thus enabling the person to somewhat see.
Artificial hearing is much more complicated then artificial seeing. First a
electrodes must be planted in the brain. Then through a microphone a computer
produces electrical pulses that are then sent to the electrodes in the brain.
But as of yet these procedures are not practical first because of the size of
the computer, it cannot be taken out of the laboratory second the cost of the
package and third the risks involved.
CONCLUSION
After all of the work and research that we have done it is very evident to us
that the brain is one of the most wondrous organs that humans could have. It
guides us through almost every second of our life. Even after exploring vast
and distant sky's to the microorganisms that exist today, the brain has never
ceased to amaze us and probably never will.
Science Essays
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