The immune system is a group of cells, molecules, and tissues that help defend the body against diseases and other harmful invaders. The immune system provides protection against a variety of potentially damaging substances that can invade the body. These substances include disease-causing organisms, such as bacteria, fungi, parasites, and viruses. The first line of defense against foreign invaders is innate immunity. Innate immunity encompasses skin, and the respiratory system, which also contains mucus that …showed first 75 words of 535 total…

…showed last 75 words of 535 total…involved in these processes are Leukocytes, or white blood cells. The macrophages and other large cells are known as Phagocytes. They destroy all bad cells and any 'trash' in the blood stream. All the B-cells and T-cells are known as Lymphocytes, who help to fight off any and all infections. The immune system is a very complex and amazing group of cells that work together to fight off and destroy foreign invaders in the body.