Sample Scholarship Essays

The Human Brain

INTRODUCTION
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.

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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 BRAINTHE 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.


BIBLIOGRAPHY
The Brain and Nervous System by Lambert, Mark copyright Macmillan Education, 1988
The Brain and Nervous System by Parker, Steve copyright Franklin Watts, 1990
Encyclopedia Britannica by Britannica, Encyclopedia Inc. copyright Encyclopedia Britannica Inc., 1986
The Incredible Machine by Geographic, National Society copyright Geographic, National Society, 1992
GLOSSARY
artificial hearing: When a person is able to hear but not naturally.

artificial seeing: When a person is able to see but not naturally.

blood brain barrier: A set of special capillaries that are only found in brain. There purpose is to filter the blood so only oxygen, glucose and water are able to enter the brain. Unfortuantly they don’t prevent narcotics from entering the brain.

brain: An organ that is pinkish-white in appearance and is located in the skull. This organ controls almost everything that the body does.

brain grafting: Brain grafting is the process of taking a thin layer of brain skin from the donor and moving to new host.

brainstem: This is what the brain had used to be early evolution, but now it only controls our basic functions such as breathing and heart rate.

capillaries: Tiny blood vessels.

cells: What all living thing are built from.

central nervous system: This the brain and spinal cord put together. Also see: brain, spinal cord.

cerebellum: This part of the brain makes sure that all of your body works together. It also keeps your balance.

cerebral cortex: This is one of the most important parts of the brain. It also is produces our thoughts, stores our memories, and plans.

cerebrospinal fluid: This what the brain floats in.

cerebrum: The cerebrum is split in to two different sides. Left and right. It is located at the front of the head.

choroid plexuses: These special blood vessels are what produce the cerebrospinal fluid.

cortex: This is the outer layer of the cerebrum.

cranium: This is the part of the skull that holds the brain.

diseases: Illnesses that can be terminal.

electrodes: They are made out metal and emit electricity, usually very little.

glucose: This is a combination of sugar and water.

grey matter: Mainly made from the cell bodies of neurons.

hemisphere: These are the two different part of the cerebrum. Almost all of the brain’s work is done there.

hormones: Chemicals that can change the chemical make up of your physical body.

hypothalmus: This part of the brain is located above the brainstem. It controls basic drives such as hunger and sex.

medulla: The medulla is almost right behind the brainstem. It helps you to digest your food.

mind: Not just the brain but the actual consciousness that we have.

nerves: Pathways that the brain uses to send messages to and from different parts of the body.

nervous system: The whole system of nerves that attach to the spinal cord.

organs: Important part of the body. The brain, heart and lungs are examples of organs.

Parkinson’s Disease: This disease causes the victim to have seizures.

pituitary: The pituitary produces hormones.

pons: A band of nerve fibre that connect the back the brain to the middle.

skull: The skull is made up of twenty-eight bones. It is located above the spinal cord. It also contains the brain.

spinal cord: This cord goes down your back. Almost all nerves in the body are connected to the spinal cord.

thalamus: The thalamus a sort of relay room. It gets messages from the lower brain area and sends them to the higher brain.

transplant: To transplant is to take something from one person and put it into another person.

white matter: White matter is tissue made from nerve fibres.

The Human Brain

The Human Brain The human being is considered to be the ultimate form of life on the earth. This is not because the human body is strong and agile. Many other animals posses skills much superior to humans and are able to perform feats humans can only dream of. The one thing that distinguishes humans from all of the other organisms on this planet is the brain. The brain is the site that controls the human body. However, unlike in animals, in man, the brain is also the site of the mind.

The mind gives humans superiority over other creatures. It provides humans with the ability to reason, to feel and to adapt. Because of this, man has achieved so much, and has also realized that much more is still ahead. During the course of evolution, ever since early Homo sapiens and his ancestors walked on the surface of the earth, man has wondered about himself, and how he relates to the natural world. People learned and adapted to new lifestyles.

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As time passed, humans learned to record history. They analyzed past events and applied this knowledge to solve problems. These processes improved as more and more people supplied their experiences to the common pool of knowledge. Such co-operation created the modern man with his superb ability to think. Many sciences were born.

Some of them centered around humans. They included, among many others, psychology and neurology. While psychology deals with the mind and human behavior, neurology is the study of the nervous system. The nervous system of the human being consists of several parts. The main structures are the brain and the spinal chord.

The system also includes nerves which sense external and internal stimuli and then relate all information to the central processing unit, i.e. the brain. Because of man’s rapid evolution in technology and medicine, humans now know a great deal more about their own nervous system then they did even a few years ago. This increase in knowledge is partly due to the recent advances in nuclear medicine. Although X-ray machines have been the chief mechanical tools for internal observations of the human body since Wilhelm Roentgen discovered X-rays in 1901, the development of computers made it possible for better and more accurate techniques to be applied to scan the human body. These methods employ various scanners like the CAT, PET, MRI and SPECT. The CAT is an acronym for Computerized Axial Tomography.

This method of scanning generally involves X-rays and enables scientists to view the inside of the head in a three dimensional format on a computer screen. PET stands for Positron Emission Tomography and it is much more complicated than the CAT scan. PET machines bombard the subject with doses of positrons — the anti-matter equivalents of the electrons. As the positrons enter the body, they encounter electrons which are escaping from radioactive elements which have been injected into the bloodstream. When the positrons and the electrons collide, they give off energy which is recorded by a computer.

The result is a far more detailed 3-D picture of the brain than the one obtained from the CAT machine. To obtain an even better image, physicians use the MRI, which stands for Magnetic Resonance Spectroscopy. With these three processes combined, every structure of the body can be easily observed. The CAT and the MRI are c ently being used to detect early signs of Multiple Sclerosis in patients who show MS symptoms. The SPECT equipment is a brand new addition to the family of body scanners.

It is still in experimental mode at several United States hospitals, but it has received much positive criticism. The SPECT, which is the short form for Single Photon Emission Computed Tomography, is a device which resembles the PET. However, it uses radiation which is less harmful and the tracers which are injected into the patient are non-radioactive isotopes of Lithium, Carbon and Phosphorus. The system is also much faster which permits quicker diagnoses. Modern technology is not the only method by which the human nervous system can be studied. Traditional surgical procedures, along with fiber optic cameras and sensors create an image of the brain that is fascinating. It is known that the brain is made up of two hemispheres, left and right, connected by a central “bridge” called the thalamus.

In the back of the human skull lies the cerebellum, an organ associated with the control of muscles and maintaining equilibrium. Other structures of the brain include the hypothalamus which governs the autonomic (non-voluntary) nervous system. Below the hypothalamus lies the pituitary gland, which is responsible for the production of various hormones. Besides the brain, modern science also studies the spinal chord and various nerves. Scientists are now able to study structures inaccessible before.

Fiber optic cables transmit images of the inside of the spinal column. Delicate hooks and blades can sample tissue from various parts of the system that would otherwise be dangerous to operate on. Nerve cells are put under Electron Scanning Microscopes to examine various parts such as axons and dendrites. Scientists even dissect cells and their chromosomes in an effort to find cures for neurological diseases. It may seem that the quest for knowledge has produced nothing but negative things. This can be observed in industrial pollution, destroyed natural habitats and uncontrollable diseases.

This might be true in the case of the environment but not in the case of the diseases (And let’s hope that the environment can be saved with additional and more dedicated research). Diseases always existed. They just have not been isolated before. And even today, there are no treatments available. There are many disorders that are associated with the nervous system.

They range from headaches to severe dementias. They have been discovered by various techniques described above. And they affect every single part of the nervous system. Some of the more well known diseases are Alzheimer’s disease, Multiple Sclerosis, epilepsy and meningitis. Alzheimer’s disease is the most important degenerative disease. It is a form of dementia, a type of disorder in which various tissues of the brain are gradually destroyed.

The results of such process include speech disturbances, short-term memory loss, disorientation, loss of mental faculties and death. Alzheimer’s is not bound by age limits. It affects not only the elderly, as most dementias do, but sometimes even attacks young adults. There is no known cure for this disease, but research continues. Recently, some theories were presented as to the origin of the disease.

Various scientific teams continually come up with possible clues. Doctors at San Francisco Athena Neurosciences institute recently made several connections between protein-splitting enzymes (Thrombin) and the destruction of nerve cells in the cerebral cortex. These cells are vital in the production of Acetylcholine, a neurotransmitter which permits smooth conduction of impulses. Their observations lead to a hypothesis which stated that if Thrombin is released from the blood stream into the fragile cavities between brain cells, it can start destroying them. However it will only do that if enzyme inhibitors are absent.

These inhibitors are present in normal human beings, and scientists are currently searching for definite evidence that persons without these inhibitors are susceptible to Alzheimer’s disease. There are also other theories about this disorder. In the late 1980’s a connection was made between Alzheimer’s and Down syndrome. Both diseases seem to have their appropriate genes on the twenty-first chromosome. The research began because it was observed that many Down syndrome patients develop Alzheimer’s at an early age. A third theory states that the disease is caused by the harmful effects of aluminum accumulation in brain tissue.

However, research in this and other areas still continues but no effective cure has been found. Alzheimer’s can be treated and slowed down by various pharmaceuticals, but it cannot be reversed. Multiple Sclerosis is a disease which, like Alzheimer’s has no know cure. This disease affects the brain and the spinal column. Specifically, it involves the destruction of the myelin sheath of the nerve fibers. The end result is non-insulated nerves which cannot effectively transmit nerve impulses.

The symptoms of this disease include loss of vision, loss of limb control and unpleasant sensations in the extremities. MS can lead to permanent paralysis. Current researchers speculate that the disorder is caused by a faulty reaction of the immune system. When the system detects certain viruses it destroys them but then also destroys the myelin sheath. However, no virus or bacteria has been found.

MS symptoms can be temporarily eased by rest and Corticosteroids. An epilepsy is defined as a sudden disturbance in mental functioning, accompanied by temporary loss of consciousness and movements of the body. Epilepsies can be sometimes avoided because the subject often hallucinates before an attack. Immediate treatment should be administered. Epilepsies are caused by a malfunction of cerebral cells. They occur when multiple nerve cells “fire” and nerve impulses are spread around the organism in an uncontrollable fashion. Such seizures can occur as a result of tumors, infections of nerve tissues, or severe trauma to the head. There is no special class of people who can be affected; anyone can have an epilepsy.

The treatment for this disorder involves drugs — anticonvulsants. Some of them, like Phenytoin, Trimethadione and Carbamazepine require only a physician’s prescription. Meningitis is one of the diseases that is caused by a bacterial infection. It is quite common but rarely fatal if treated promptly. There are several types of meningitis, but they are classified into two groups. Meningococcal, epidemic and spinal meningitis are diseases which are directly associated with the meninges — membranes which envelop the brain and the spinal chord and protect them from harmful outside factors. The other group of disorders (for example, tuberculous and syphilitic meningitis) affect a different part of the body and that part in turn infects the membranes.

The symptoms of meningitis include vomiting, headaches and stiffness of the neck. These are caused by inflammations and collections of pus between the membranes. Meningitis can be treated by antibiotics, but treatment has to be immediate since sometimes the pressure caused by the collected fluids and pus can cause death. Vaccinations are also available against bacterial meningitis. Neurology is truly a fascinating science. It allows humans to explore the mysteries of the brain and therefore allows them to see why man behaves like he does.

This is because psychology is entirely based on the physical side of life. Also, humans will always strive to reach higher levels of intellect and along the process, perhaps they will discover the cures for today’s incurable diseases. Or maybe they will invent a mechanism which will allow them to see into the very hearts of chromosomes and they will be able to transform man into an even more spectacular creature.

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