The Way the Immune System Works Essay

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THE IMMUNE SYSTEM

Definition of the Immune System The human immune system is a collective network of tissues, glands, and organs that work in a coordinated effort with each other to guard our bodies from foreign antigens such as viruses, bacteria, and infection causing microorganisms. For the immune system to work properly, two things must happen: first, the body must recognize that it has been invaded, either by pathogens or toxins or by some other threat. Second, the immune response must be activated quickly, before the invaders destroy many body tissue cells. For the immune system to respond effectively, several conditions must be in order, including the proper interaction of non-specific and specific defenses. The nonspecific
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The spleen is a flattened organ located in the upper left portion of the abdomen. The spleen serves as an immunologic blood filter. It filters your blood and it destroys old or damaged blood vessels. It is made up of B-cells (B-lymphocytes), T-cells (T-lymphocytes), dendritic cells, and macrophages. The purpose of the T-cells and B-cells, is to identify the foreign particles and create antibodies against it. The lymph nodes are small, roundlike, bean shaped organs located in the lymphatic vessels. The lymph nodes function as an immunologic filter for the body. It filters particulate and soluble molecules out of lymph, thus attracting immunogens for immune system stimulation. Lymph is the interstitial tissue fluid picked up by the lymphatics for transport to the lymph ducts that empty into the veins. Lymph nodes are also composed mostly of T-cells, B-cells, dendritic cells and macrophages. When foreign antigens enter the lymph nodes by either lymphatic vessels, or by circulation, these cells identify them as foreign antigens and respond accordingly.
Cells of the Immune System Two types of cells exist in the immune system: myeloid cells and lymphoid cells. There are four types of myeloid cells. They are granulocytes, monocytes, macrophages, and dendritic cells. Granulocytes are leukocytes (white blood cells) containing granules in the cytoplasm. They act as a first line of defense, rushing toward an
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