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ARRoGANT CoURiERS WiTH ESSaYS
Grade Level: Type of Work Subject/Topic is on:
[ ]6-8 [ ]Class Notes [Essay on the Human Brain]
[x]9-10 [ ]Cliff Notes [ ]
[ ]11-12 [x]Essay/Report [ ]
[ ]College [ ]Misc [ ]
Dizzed: 10/94 # of Words:1794 School: ? State: ?
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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. 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.