• Your Body's Best Defense Against Germs:  The Immune System
     
     
    Every day, your body fights off infections, germs, bacteria, and parasites.  It is destroying these invaders, called pathogens, with the help of its number one defense:  the immune system.  The immune system's job is to keep your body healthy.  This requires many different parts of the body to work together against pathogens.  Here are the main components of your immune system:
     
    Tonsils
    Located in the back of your throat, the tonsils protect the entrance of your respiratory and digestive systems by destroying bacteria with the help of white blood cells.
     
    Thymus Gland
    Located underneath the middle of your breastbone and above your heart, the thymus gland stores white blood cells until they are mature, and then provides them with specific jobs.
     
    Lymph Nodes
    Small, bean-shaped  nodules on the lymphatic vessels, lymph nodes are located primarily in your armpits and groin regions.  They filter pathogens out of the lymphatic system.
     
    Bone Marrow
    Located inside your body's bones, it produces red and white blood cells.  Red blood cells carry oxygen to other cells and body parts, and remove carbon dioxide.  White blood cells look for and destroy pathogens.  The different types of white blood cells are phagocytes, B-cells and T-cells.
     
    Spleen
    The largest lymphoid organ in the lymphatic system, the spleen is located to the left of your stomach.  The spleen removes pathogens from the blood as it passes through.
     
    Liver
    Your body's largest internal organ, the liver contains white cells.  These cells destroy bacteria in the blood as it passes through the liver.  It also processes nutrients found in the blood and produces bile used in digestion.
     
    Blood
    Red and white cells travel throughout your body's blood vessels.  While white blood cells defend against pathogens, your red blood cells nourish your body.