How for the specific recognition of foreign agents




How do white blood cells protect the body from disease?

Function of white blood cells

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Matthew Mullett










Biology 111

Mrs. Standring

December. 18, 2017

            The body uses the immune system to defend its self from infections and viruses. The immune system has a series of methods used to protect your body. The most important one are your white blood cells or also known as leukocytes. These cells defend the body against infection and disease by ingesting foreign materials and debris, by destroying infectious agents and cancer cells, or by producing antibodies (Britannica 1). White blood cells are found in lots of places throughout the body. Most are found outside of circulation within tissue where they fight infections; the few found in the blood stream are in transit from one site to another (Britannica  3). The white blood cells are grouped into three major classes: Lymphocytes, Granulocytes, and Monocytes – each with a different function (Britannica 3). As every thing else in the world, the white blood cells can develop conditions that can have a fatal effect on a person.

            Lymphocytes are really what is associated with white blood cells. The fact that they encounter a foreign invader or infection and destroy it. Lymphocytes are responsible for the specific recognition of foreign agents and their subsequent removal from the host (Britannica 4). This type of cell is then subdivided into T cells and B cells. The B cells or B lymphocytes are what produce antibodies (Yamini 2). B cells are like the body’s military intelligence that seek out targets and send defense to destroy them (Yamini 2). Then there are the T cells that destroy antigens that have been tagged by antibodies or cells that have been infected or somehow changed (Yamini 3). T cells are like the soldiers, they destroying the invaders that the intelligence system (B cells) has identified (Yamini 2). Another name for T cells are actually “Killer cells”. About 25 to 35 percent of white blood cells are lymphocytes in a healthy person (Britannica 4).

            Granulocytes are the most numerous of the white blood cells that rid the body of large pathogenic organisms such as protozoans or helminthes and are also key mediators of allergy and other forms of inflammation (Britannica 4). Granulocytes are subdivided into three categories: Neutrophils, Eosinophils, and Basophils (Britannica 5). Neutrophils are the first cell types to arrive at an infection where they engulf and destroy the infectious micro organisms through a process called phagocytosis (Britannica 5). Phagocytosis is when cells chew up the invading organisms (Yamini 2). Although after a neutrophil engulfs any foreign particles they self-destruct (Dority 1). About 50 to 80 percent of all white blood cells are neutrophils (Britannica  5). Basophils have granules that contain a number of chemicals, including histamine that is important in inducing allergic inflammatory responses (Britannica 5) and heparin (Dority 2). Well what do these two chemicals do exactly? Heparin is an anti-coagulant, meaning it prevents blood cells from clotting too quickly. Histamine is a vasodilator that is commonly released during allergic reactions to increase blood flow (Dority 2). Eosinophils are what destroy parasites and also help modulate inflammatory responses (Britannica 5). How eosinophils fight parasites are by releasing chemical mediators, peroxides, nucleases and lipases, by a process called degranulation with target pathogens (Dority 2).

            The third and final class are monocytes. Monocytes originate in the bone marrow and develop into large macrophages in the bloodstream (Dority 1). These cells are scavengers and are therefore effective at direct destruction of pathogens and clean up cellular debris from sites of infection (Britannica 6). In other words, monocytes are what clean up the mess left behind from the destruction of a foreign invader. Between 4 and 8 percent of white blood cells are monocytes in your blood (Britannica 6).

            White blood cells are also apart of another system known as the lymphatic system. This system is made up of lymph nodes that work like filters to remove any germs that could make you sick, in this case it’s a clear fluid called lymph that contains leukocytes (white blood cells) inside of it (article 2 pg.1).

            All of these different classes and subdivisions of white blood cells aren’t because there are so many. Its because specific types of cells are associated with different illnesses which reflect the special function of that cell type in body defense (Britannica 6). This is seen in newborns who have a high white blood cell count that gradually to the adult level during childhood. This is a natural response as newborns are more susceptible to getting an infection (Britannica 6).

            How do white blood cells know then when it s time for them to destroy a foreign invader? It was found that white blood cells make a protein called HIF-1 that boost the production of antibacterial compounds when oxygen levels begin to drop, or when the cell encounters a harmful bacterium (Coombs pg.1). “turning on the HIF-1 is like a white blood cell pulling out it’s sword as it enters infected tissue” (Coombs pg. 1). Therefore, if they were always making killer compounds it might destroy the good cells and waste good energy (Coombs Pg.1).

            Some people have problems with their immune system meaning it may respond to non-dangerous materials in a potentially pathogenic way. Allergies, an example of this is when the immune system overreacts and treats something harmless like peanuts as though is was really dangerous to the body (article 2 pg.2). Well what is it that causes this? Its certain medical conditions such as lupus that cause the immune system to fight the good cells and this can cause problems (Britannica Pg.2).

             The immune system is a well regimented army working together to combat the dangerous foreign invaders. Its battalions consist of front line white cells in the form of neutrophils, Special operations white cells in the form of basophils and finally eosinophils. Together these types of cells are what make up granulocytes cells that rid body of disease. While the lymphocytes are what find diseases or infections and tell the granulocytes to destroy them.
















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The Editors of Encyclopædia Britannica. “White blood cell.” Encyclopædia Britannica         Encyclopædia  Britannica, inc., 16 Feb. 2017,       cell.

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