Medical brain notes 7

  AN OVERVIEW OF THE NERVOUS SYSTEM   The  Nervous system  comprises of the brain, the spinal cord, the nerves emanating from them and their innervations of muscle fibres. The human race is superior and special to the other living beings due to the unique anatomy and physiology of human nervous system. Especially the cortex of the brain (the grey layer of the brain surface) is highly evolved and complex. Other organs of the human beings are similar or even weaker as compared to those of the other animals, but the humanrace proves superior because of the exceptional mental power & ability, as well as logic, memory and vocabulary all due to the cortex of the brain. The cortex consists of approximately 100 billion neurons. According to an estimate, an average person uses about 5 to 10 percent of his brain capacity, but a genius uses his brain up to 15 percent. Therefore it can be said that any person can become a genius by learning how to use his brain more and putt...

  Basic unit - a neuron & neural organisation As mentioned earlier, the Nervous System comprises of the brain, the spinal cord, the nerves emanating from them and their innervations of muscle fibres (i.e. peripheral nervous system). The brain immediately confronts us with its great complexity. The human brain weighs only 1200 to 1400 gms. but contains about 100 billion neurons. Although that extraordinary number is of the same order of magnitude as the number of stars in the Milky Way, it alone cannot account for the complexity of the brain. A major part of the complexity arises from the rich diversity of nerve cells, or neurons, which the famous neuroanatomist Ramon y Cajal described as “the mysterious butterflies of the soul”. Neurons, or nerve cells, are the basic building blocks of the brain. A neuron has three main parts - a cell body containing the nucleus, dendrites which are specialized branches for receiving information from other neurons, and axons which are specializ...

  COMMON DISEASES : After understanding the basics of the brain, we will now classify the common diseases of the brain and nervous system: The above mentioned diseases are known as neurological disorders. A neurologist or any experienced physician can treat them. Diseases of the psyche (mana) are called psychiatric disorders e.g. depression, anxiety, psychosis, neurosis, personality problem, psychosexual diseases etc. A qualified psychiatrist should treat these diseases. Normally in psychiatric diseases investigations like CT scan, E.E.G. and Lumber Puncture are normal. Many a times there can be similar symptoms creating confusion. For instance a change in the personality of a patient may either be due to depression or brain tumor (frontal or corpus callosal region). This can result in serious lapse in diagnosis. Therefore, in each psychiatric case a detailed history as wellas physical examination is essential. If in doubt, it is always better to get a test or two (like CT Scan or ...

  NEURORADIOLOGY - THEIMAGING OF THE BRAIN A doctor normally diagnoses and treats the patient through observations of symptoms, history etc. Many a times when it becomes necessary to know the location, extent and damage caused by a disease lying inside the body, radiology- neuroradiology becomes helpful and and necessary. Radiology-neuroradiology consists of Screening, X-Rays, Ultrasound, CT scan, and MRI etc. X-Ray : The “miraculous rays” X-Rays which could look-make structures inside the body were discovered in 1895 by a German scientist Mr: Roentegen. Thereafter these rays have been used in all possible innovative ways in the medical field. Sunrays, X-Rays, Microwave, Radio waves are all electro magnetic rays in scientific terminology. The only differentiating factor between them is their energy- content. Radio and television waves do not have much energy and so though they are present all around us in innumerable numbers, they cannot harm us and we are still alive. The energy f...

  X-Ray : The “miraculous rays” X-Rays which could look-make structures inside the body were discovered in 1895 by a German scientist Mr: Roentegen. Thereafter these rays have been used in all possible innovative ways in the medical field. Sunrays, X-Rays, Microwave, Radio waves are all electro magnetic rays in scientific terminology. The only differentiating factor between them is their energy- content. Radio and television waves do not have much energy and so though they are present all around us in innumerable numbers, they cannot harm us and we are still alive. The energy from the X-Rays is 10,000 to 15,000 times more powerful than light and therefore can penetrate through objects. An amazing fact of nature is that the human eye can perceive only the sun rays and the rest of the rays are invisible to us. The common X-Rays only give a rough picture of the skull or a one dimensional picture, but the depth of any feature cannot be judged, e.g. if there is a tumor inside thebrain i...

  C T Scan : (Computed Axial Tomography) X-rays are used to give us a picture of different parts of the body. However, since we are now discussing about the diseases of the brain, it is necessary to know how X-Rays are helpful in this context. In the previous chapter we learned that the brain is well protected in the skull and therefore X-Rays are only able to give us the information of the skull. In-depth information regarding the inner structure cannot be obtained. The CT scan machine invented by a British Scientist Honsfield solved this problem. CT scan or CAT Scan is Computed Axial Tomography. CT scan also uses the X-Ray technology but with the help of the computer a three-dimensional view of the body is created. If there is a tumor in the brain, its depth and position can be determined by dividing the brain into imaginary parts like slices of bread, and each part is X-Rayed from various angles. The computer then calculates and creates a three- dimensional picture, which determ...

  CT Scan Machine : The CT Scan Machine is like a cubical box and is called Gantry. Within this box lies a two feet long circular tunnel. The stretcher like table on which the patient lies, can be moved in all directions upward, downward and side ways. The part of the body to be examined is kept at the center of the tunnel. The X-Ray tube lies in the middle of the tunnel, and rotates in a circular motion photographing the body part from each angle. These photographs are reflected on the detector, a computer carries out accurate calculations, divides the area into slices and then with the help of laser camera photographs are taken. The entire procedure takes about 15 to 30 minutes and during this time the patient has to lie still. On an average twenty photographs are taken on a 14" × 17" X-Ray film, which are interpreted by the radiologist and a report is made. A CT scan can gives detailed informationof organs right from the brain to the spinal cord and lungs to the stomach, s...