Immune System
The immune system in a vertebrate (an organism with a backbone) consists of all the cells and tissues that recognize and defend the body against foreign chemicals and organisms. For example, suppose that you receive a cut in your skin. Microorganisms living on your skin are then able to enter your body. They pass into the bloodstream and pass throughout your body. Some of these microorganisms are pathogenic, that is, they may cause illness and even death. As soon as those microorganisms enter your body, its immune system begins to identify them as foreign to your body and to produce defenses that will protect your body against any diseases they may cause.
The study of the immune system is known as immunology and scientists engaged in this field of research are...
[The entire page is 2107 words long]
