Antibody Definition and Immune System

Antibody Definition Antibody is a unique molecule that binds with a specific antigen so the immune system can neutralize or destroy the antigen. Antigens are molecular markers on the surfaces of cells that identify the cells to the immune system. Antibodies are the immune system’s infantry, patrolling the blood and lymph circulations and responding to fight infection when invading pathogens breach the barriers intended to […]

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Immune system – Definition

Immune System Definition The structures, substances, and processes that protect the body from infection. These include organs, tissues, cells, and molecules. The immune system functions in close collaboration with the nervous system and the endocrine system. The main organs and tissues of the immune system include Bone marrow Thymus Spleen Lymph nodes Blood Lymph Adenoids and tonsils […]

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Nose – Associated Lymphoid Tissue (NALT)

Nose – Associated Lymphoid Tissue Definition Loosely organized collections of lymph tissue embedded in the mucous membrane lining (mucosa) of the nasal passages and sinus cavities. Nasal mucous, which the nasal mucosa secretes, is one of the body’s front-line protective mechanisms, providing a physical barrier that repels or traps foreign substances such as bacteria, viruses, […]

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Antibody-mediated Immunity and B Cells

Antibody-mediated Immunity Definition Antibody-mediated Immunity is the mechanism through which specialized immune cells, primarily B-cell lymphocytes, carry out the immune response to protect the body from extracellular pathogens (disease-causing entities, such as bacteria and other microbes, present in the blood or lymph that have not invaded the body’s cells). Antibodymediated immunity, also called humoral immunity, encompasses the functions of […]

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Immunodeficiency – Definition and Information

Immunodeficiency Definition The absence of immune system components essential for proper immune response and protection from infection – may be congenital (present at birth) or acquired (develop later in childhood or adulthood). As well, immunodeficiency is a consequence of therapies intended to compromise immune function, such as radiation therapy, chemotherapy, and immunosuppressive therapy. Congenital Immunodeficiency Congenital immunodeficiency is genetic (the result of a gene […]

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Peyer’s Patches

Peyer’s Patches Definition and Function Small, nodular clusters of lymphoid tissue scattered throughout the mucous membrane lining of the small intestine. Though not encapsulated as are lymph nodeS, Peyer’s patches are more distinct and organized than other mucosa-associated lymphoid tissue (MALT). Peyer’s patches are elements of gut-associated lymphoid tissue (GALT), a subset of MALT. GALT lies beneath the epithelial […]

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Antigen – Definition, Cancer and Antibody

Definition of Antigens A molecule that resides on the surface of a cell membrane and is capable of stimulating an immune response. Antigen molecules are either lipoproteins (lipid and protein) or glycolipids (lipid and glucose). Each cell has numerous antigens that that identify it to the immune system. Cells that belong to the body bear antigens that mark […]

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Immunoglobulin – Definition

Immunoglobulin Definition Immunoglobulin is a protein structure the immune system produces. Immunoglobulins are the foundation molecules for the formation of antibodies. Immunoglobulins circulate in the blood. The immunoglobulin’s class designation reflects its molecular structure, which in turn dictates the action of the immunoglobulin. The five major classes of immunoglobulin provide different kinds of antibodies: Immunoglobulin A (IgA) is the main […]

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Prostaglandins – Definition and Function

Prostaglandins Definition A large family of fast-acting lipid mediators primarily responsible for initiating inflammation, fever, and pain during the immune responsE. Prostaglandins are also vital for numerous functions throughout the body. Thromboxane, one of the prostaglandins, facilitates platelet aggregation to aid coagulation (blood clotting). Other prostaglandins facilitate calcium transport to and from cells, the onset and progression of labor during childbirth, […]

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Antiphospholipid Antibodies and Antibody Syndrome

Antiphospholipid Antibodies Definition, Syndrome Autoantibodies the immune system produces that attack phospholipids, fatty substances in the cell membranes of blood cells and connective tissue cells. Antiphospholipid antibodies interfere with blood clotting (coagulation) and are present in a number of autoimmune disorders that affect connective tissue, such as rheumatoid arthritis (affecting the joints) and vasculitis (affecting the blood vessels). These antibodies are also present […]

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