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We Know: How the Immune System Works
What is The Immune System?
The immune system contains the network of cells, tissues, and organs that defend against infectious organisms and bacteria. It can distinguish between "self" and "non-self" preventing attack on existing body tissues. Any non-self substance (bacterium, virus, etc.) will trigger an immune response (antigen).
Where is the immune system located?
The organs of the immune system (lymphoid organs) are positioned throughout the body. They contain the white blood cells that operate the immune system. Included are:
- The bone marrow is soft tissue in the hollow center of bones that creates all blood cells, including the immune cells.
- The thymus is an organ that lies behind the breastbone where the lymphocytes (T cells) mature.
- The spleen is a flattened organ at the upper left of the abdomen.
- Clumps of lymphoid tissue like the tonsils, adenoids, and appendix.
- Lymph nodes (small, bean-shaped clusters that sit along the lymphatic vessels) found in the neck, armpits, abdomen, and groin contain specialized compartments where immune cells congregate, and encounter antigens.
How do immune cells work?
Immune cells release different antibodies, each with a different function, that destroy foreign invaders. Antibodies belong to a family of large protein molecules known as immunoglobulins. Some types of antibodies or immunoglobins are:
- Granule-containing cells such as eosinophils that attack parasites
- Basophils, which release granules containing histamine and other allergy-related molecules.
- Cytotoxic T helps rid your body of cells that have been infected by viruses as well as cells that have been transformed by cancer. They are also responsible for the rejection of tissue and organ grafts.
- Interferons are naturally occurring cytokines that may boost the immune system's ability to recognize cancer as a foreign invader.
- Cytokines encourage cell growth, promote cell activation, direct cellular traffic, and destroy target cells--including cancer cells.
- Scavenger cells and IgA antibodies prevent microbes from getting into your body through the skin and mucous membranes.
What are immune system disorders?
Allergies such as hay fever and hives are the result of an immune response. When encountering the organism for the second and consecutive times, the body releases powerful chemicals that cause the wheezing, sneezing, and other symptoms of allergy.
What are autoimmune disorders?
Autoimmune disorders happen when the immune system breaks down or is overwhelmed. They include:
- T cells that attack pancreas cells contribute to diabetes
- An autoantibody known as rheumatoid factor is common in persons with rheumatoid arthritis.
- When the immune system is lacking one or more of its components, the result is an immunodeficiency disorder like HIV and AIDS.
- When normal cells turn into cancer cells, some of the antigens on their surface change and can develop into tumors.
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