Q What is the composition and function of immune system?
The immune system is the bodys defense system. It is a network of cells, tissues, and organs that work together to defend the body against attacks by foreign invaders. These are primarily microbes tiny organisms such as bacteria, parasites, and fungi that can cause infections. Immune system has the cells involves white blood cells, or leukocytes, which come in two basic types that combine to seek out and destroy disease-causing organisms or substances. The two basic types of leukocytes are: (1) phagocytes, cells that chew up invading organisms. (2) lymphocytes, cells that allow the body to remember and recognize previous invaders and help the body destroy them.