Online Education Blog

How infectious diseases are passed one person to another in various ways, this very important question. And these diseases are caused by micro organism and worms. Some of them are tuberculosis, malaria, chicken fox and cholera. But human skin and blood fight against germs to prevent such kind of disease. First of all, the skin and the mucous membranes of our body help us to keep out germs. There are glands in the skin, which produce oily substances to provide a protective cover to the surface to the skin. Perspiration helps us to eliminate certain wastes and germs out of the skin; perspiration also contains a special chemical known as lysozyme which destroys germs. Lysoxyme is also found in tears, saliva, nasal secretion and tissue fluids. Many types of germs, which happen to reach our stomach, are destroyed by strongly acidic stomach juices. The germs, which gain entry into our body, reach our organs or survive in the stomach, take nourishment from our body to multiply. Then they begin to destroy our body cells and also secrete toxic or poisonous substances. Unless their activity is checked they secrete enough toxins to make us feel sick. But more often they are overpowered by our body. Our body has an elaborate defense system comparable to the defense forces of a country. This defense system is called the immune system. The defense force is in the form of special cells, called white blood cell (W.B.C), which circulate throughout the body along with blood. The W.B.C. is of various types and fights the invader in a variety of ways. During many kinds of infection, an automatic increase in their total number is triggered. The number might double, triple or quadruple depending upon the severity of infection. Therefore, doctors determine the number of W.B.C. in blood by observing drop of it under the microscope. When germs attack our body, special types of W.B.C. migrate to the infected site and destroy the invader germs by engulfing them. These cells are called engulfing cells. Interestingly, when the fight is over, other type of W.B.C. are directed to move to the site to remove dead germs and dead W.B.C. the pus that is generally present at the site of infection contains a large number of dead cells and germs. Another kind of W.B.C. produce a chemical weapon called antibodies, which attack poison or toxic substances to make them ineffective. These antibodies also tag the invader, so that the engulfing cells easily recognize it. yet another type of W.B.C. work as killer cells and directly destroy the invader or the infected body cell. Some W.B.C. which have for the first time encountered a specific invader are held in reserve as trained cells, which can work for subsequent encounter effectively. The whole body defense mechanism goes into action as soon as disease germs enter the body and cause an alarm signal to be generated. Quite often, our body is effectively able to deal with the infection and all symptoms like fever or inflammation subside by themselves, but at other times, so we can say medicine must be used to supplement the body defense mechanism for every human being.