Unit 12: The Immune System
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49 terms
Terms | Definitions |
|---|---|
 acquired immune deficiency syndrome (AIDS) | an infectious disease caused by the human immunodeficiency virus (HIV); attacks and destroys T cells, thus weakening the immune system |
| adaptive immune response | a response to invading toxins or microbes in which immune cells are activated by a specific invader, selectively destroy that invader, and then "remember" the invader, allowing a faster response if that type of invader reappears in the future |
| adaptive immune system | a widely distributed system of organs (including the thymus, bone marrow, and lymph nodes), cells (including macrophages, dendritic cells, B cells, and T cells), and molecules (including cytokines and antibodies) that work together to combat microbial invasion of the body; the _______ _______ ________ responds to and destroys specific invading toxins or microbes |
| allergy | an inflammatory response produced by the body in response to invasion by foreign materials, such as pollen, that are themselves harmless |
| antibiotic | chemicals that help to combat infection by destroying or slowing down the multiplication of bacteria, fungi, or protists |
| antibody | a protein, produced by cells of the immune system, that combines with a specific antigen and normally facilitates the destruction of the antigen |
| antigen | a complex molecule, normally a protein or polysaccharide, and stimulates the production of a specific antibody |
| autoimmune disease | a disorder in which the immune system attacks the body's own cells or molecules |
| B cell | a type of lymphocyte that matures in the bone marrow, and that participates in humoral immunity; gives rise to plasma cells, which secrete antibodies into the circulatory system, and to memory cells |
| cancer | a disease in which some of the body's cells escape from normal regulatory processes and divide without control |
| cell-mediated immunity | an adaptive immune response in which foreign cells or substances are destroyed by contact with T cells |
| clonal selection | the mechanism by which the adaptive immune response gains specificity; an invading antigen elicits a response from only a few lymphocytes, which proliferate to form a clone of cells that attack only the specific antigen that stimulated their production |
| complement | a group of blood-borne proteins that participate in the destruction of foreign cells, especially those to which antibodies have bound |
| constant region | the part of an antibody molecule that is similar in all antibodies of a given class |
| cytokine | any of several chemical messenger molecules released by cells that facilitate communication with other cells and transfer signals within and between the various systems of the body. _________ are important in cellular differentiation and the adaptive immune response |
| cytotoxic T cell | a type of T cell that, upon contacting foreign cells, directly destroys them |
| dendritic cell | a type of phagocytic leukocyte that presents antigen to T and B cells, thereby stimulating an adaptive immune response to an invading microbe |
| emerging infectious diseases | a previously unknown infectious disease (one caused by a microbe), or a previously known infectious disease whose frequency or severity has significantly increased in the past two decades |
| fever | an elevation in body temperature caused by chemicals (pyrogens) that are released by white blood cells in response to infection |
| helper T cell | a type of T cell that other immune cells recognize and act against antigens |
| histamine | a substance released by certain cells in response to tissue damage and invasion of the body by foreign substances; promotes the dilation of arterioles and the leakiness of capillaries and triggers some of the evens in the inflammatory response |
| human immunodeficiency virus (HIV) | a pathogenic virus that causes acquired immune deficiency syndrome (AIDS) by attacking and destroying the immune system's helper T cells |
| humoral immunity | an immune response in which foreign substances are inactivated or destroyed by antibodies that circulate in the blood |
| immune system | a system of cells, including macrophages, B cells, and T cells, and molecules, such as antibodies and cytokines, that work together to combat microbial invasion of the body |
| inflammatory response | a nonspecific, local response to injury to the body, characterized by the phagocytosis of foreign substances and tissue debris by white blood cells and by the walling off of the injury site by the clotting of fluids that escape from nearby blood vessels |
| innate immune response | nonspecific defenses against many different invading microbes, including phagocytic white blood cells, natural killer cells, the inflammatory response, and fever |
| leukocyte | any of the white blood cells circulating in the blood |
| lymph node | a small structure located on a lymph vessel, containing macrophages and lymphocytes (B and T cells). Macrophages filter the lymph by removing microbes; lymphocytes are the principal components of the adaptive immune response to infection |
| lymphocyte | a type of white blood cell (natural killer cell, B cell, or T cell) that is important in either the innate of adaptive immune response |
| macrophage | a type of white blood cell that engulfs microbes and destroys them by phagocytosis; also presents microbial antigens to T cells, helping stimulate the immune response |
| major histocompatibility complex (MHC) | a group of proteins, normally located on the surfaces of body cells, that identify the cell as "self"; also important in stimulating and regulating the immune response |
| mast cell | a cell of the immune system that releases histamine and other molecules used in the body's response to trauma and that are a factor in allergic reactions |
| memory B cell | a type of white blood cell that is produced by clonal selection as a result of the binding of an antibody on a B cell to an antigen on an invading microorganism. ______________ __ cells persist in the bloodstream and provide future immunity to invaders bearing that antigen |
| memory T cell | a type of white blood cell that is produced by clonal selection as a result of the binding of a receptor on a T cell to an antigen on an invading microorganism. ___________ __ cells persist in the bloodstream and provide future immunity to invaders bearing that antigen. |
| microbe | a microorganism |
| natural killer cell | a type of white blood cell that destroys some virus-infected cells and cancerous cells on contact; part of the innate immune system's nonspecific internal defense against disease |
| neutrophil | a type of white blood cell that engulfs invading microbes and contributes to the nonspecific defenses of the body against disease |
| pathogen | an organism (or a toxin) capable of producing disease |
| phagocyte | a type of immune system cell that destroys invading microbes by using phagocytosis to engulf and digest the microbes. |
| plasma cell | an antibody-secreting descendant of a B cell |
| regulatory T cell | a type of T cell that suppresses the adaptive immune response, especially by self-reactive lymphocytes, and appears to be important in the prevention of autoimmune disorders |
| severe combined immune deficiency (SCID) | a disorder in which no immune cells, or very few, are formed; the immune system is incapable of responding properly to invading disease organisms, and the individual is very vulnerable to common infections |
| spleen | the largest organ of the lymphatic system, located in the abdominal cavity; contains macrophages that filter the blood by removing microbes and aged red blood cells, and lymphocytes (B and T cells) that reproduce during times of infection |
| T cell | a type of lymphocyte that matures in the thymus, and that recognizes and destroys specific foreign cells or substances or that regulates other cells of the immune system |
| T-cell receptor | a protein receptor, located on the surface of a T cell, that binds a specific antigen and triggers the immune response of the T cell |
| thymus | an organ of the lymphatic system that is located in the upper chest in front of the heart and that secretes thymosin, which stimulates maturation of T lymphocytes of the immune system |
| tonsil | a patch of lymphatic tissue, located at the entrance to the pharynx, that contains macrophages and lymphocytes; destroys many microbes entering the body through the mouth and stimulates an adaptive immune response to them |
| vaccine | an injection into the body that contains antigens characteristic of a particular disease organism and that stimulates an immune response appropriate to that disease organism |
| variable region | the part of an antibody molecule that differs among antibodies; the ends of the _________ ______ of the light and heavy chains form the specific binding sites for antigens |
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