Immune system is the foundation for good health.
Components of Immune System
Our immune system, made of a network of cells, tissues, and organs, work together to protect us when micro-organisms invade the body. The system can distinguish what belongs to the body from everything foreign to it, and protect it against infections by foreign substances.
Let’s say a microorganism breaches one of your natural defenses (i.e., skin, mucosal surfaces, etc.), and you just received a cut on your finger. Your body now faces the risk of a full-scale invasion from bacteria or viruses. Let’s see how your body protects you from such a threat.
The cells at the site of injury have been destroyed by the cut and the body responds by dilating the blood vessels and increasing the blood flow. These cells also alert other cells of the immune system of the impending danger and promote migration of other cells.
This brings the immune system’s primary defensive immune cells – the white blood cells or leukocytes – to the damaged area in great numbers.
Leukocytes come in two basic types: phagocytes and lymphocytes. Phagocytes initiate search-and-destroy attack on invading organisms. Neutrophils are phagocytes which phagocytize foreign material. They contain granules filled with potent chemicals capable of destroying microorganisms.
Monocytes are phagocytes which circulate in the blood, then migrate into tissues where they develop into macrophages (”big eaters”). They find and “swallow” bacteria, viruses, and dead or injured body cells and throw worn-out cells and debris out of the body.
Lymphocytes: Producing Antibodies Against Antigens
Foreign substances are capable of triggering an immune response in the body and are called antigens.
Antigens are proteins that may be contained within or on bacteria, viruses, other microorganisms, or cancer cells. Antigens may also exist independently—for example, as food molecules or pollen. Bacteria and viruses have antigens on their surface which are different from the body’s “self” antigens.
A normal immune response consists of recognizing the potentially harmful pathogenic antigens, activating and mobilizing forces to attack it.
Lymphocytes are one of the chief components of the immune system which is responsible for this. They are formed in lymphatic tissue throughout the body including the spleen, thymus, tonsils, and lymph nodes.