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.
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.