Immune System in the Human Body
As our country is guarded by the soldiers so is the living body guarded by a certain mechanism called the immunity or the immune system. If the immune system is weakened or destroyed the body falls ill. We have a special system in our body called the immune system. An immune system is a collection of mechanism within an organism that protects against the pathogens by identifying and killing them.
We know that small pox is a fatal disease that has been eradicated successfully. However small pox epidemics were common till a few years ago. At one time small was very significant disease in most countries of the world. Millions of people died because of this deadly disease. As small [pox was a contagious disease, people used to be scared to coming close to the person suffering from it. However people who already suffered and survived this disease did have this fear. This is because the survivors were immune for the rest of their lives. So suffering from a disease once can prevent subsequent attacks of the same disease. This is the basis of immunity and immunization. Immunity is the body’s ability to fight off foreign substances or microbes by producing antibodies that can destroy or neutralize these foreign substance or cells.
But how does this happen? This happens because when the immune system encounters a pathogen, it responds against it. This response helps the immune system to recognize the particular pathogen more efficiently. This response is then retained after the pathogen has been destroyed in the form of immunological memory. This allows even more effective protection during encounter with the same pathogens. Next time when that particular pathogens enters the body, the immune system eliminates this infection even faster than the first time attack. This forms the basis of the principle of immunization. Immunization is the term used for introducing dead or weakened germ in the body of living beings for developing immunity or resistance against a particular disease.