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62 Cards in this Set
- Front
- Back
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immune system |
- protects against assaults on the body |
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external assaults |
- microbes - protozoans, bacteria, viruses |
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internal assaults |
- abnormal cells reproduce and from tumors that my become cancerous and spread |
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HLA |
- human leukocyte antigen -marks every cell in body and self - the MHC (major histocompatibility complex) in humans |
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self tolerance |
- ability of our immune system to attack abnormal or foreign cells but spare our own normal cells |
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innate immunity |
- provides a general, non specific defense against anything that is not "self" - skin, mucous membranes, gastric pH - genetic mechanisms put in place during development in the womb |
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adaptive immunity |
- specific defense against specific threatening agents - resistance developed after birth |
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innate immunity primary cells |
- epithelial barrier cells - phagocytes (neutrophils, macrophages) - natural killer cells - chemicals - complement and interferon |
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adaptive immunity primary cells |
- lymphocytes - T and B cells |
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cytokines |
- any of several kinds of chemicals released by cells to promote innate and adaptive immune responses - interleukin, interferon, leukotriene |
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species resistance |
- genetic characteristics of an organism or species defends against pathogens |
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Lines of defense |
1st line - mechanical and chemical barriers (innate) 2nd line - inflammation (innate) 3rd line - adaptive immunity |
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mechanical and chemical barriers |
- sebum, mucus, enzymes, and hydrochloric acid |
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inflammatory response |
- tissue damage elicits responses to counteract injury and promote normalcy |
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inflammation mediators |
- histamine, kinins, prostaglandins |
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chemotactic factors |
- substance that attract white blood cells to the area by chemotaxis |
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signs of inflammation |
- heat, redness, pain, and swelling |
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systemic inflammation |
- occurs from a body-wide inflammatory response |
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chemotaxis |
- chemical attraction of cells to the source of the chemical attractant |
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diapedesis |
- process by which immune cells squeeze through the wall of a blood vessel to get to the site of injury/infection |
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APCs |
- antigen presenting cells - phagocytes - ingest foreign particles and display protein segments as antigens on their surfaces to trigger an immune response when recognized by a specific adaptive immune cell |
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neutrophil |
- most numerous type of phagocyte - first to arrive at site of injury - migrates out of blood stream during diapedesis - forms pus |
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macrophages |
- phagocytic monocytes grow large after migrating from the bloodstream - langerhins in skin, kupffer cells in liver, microglia in nervouse, histiocytes in CT |
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dendritic cell |
- type of macrophage with long branches or extensions |
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Natural Killer Cells (NK Cells) |
- kills target cell if the killer inhibiting antigen on the NK cell does not bind to a proper MHC surface protein - lyse cells by damaging the plasma membrane |
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interferon |
- protein synthesized and released into circulation by cells invaded by a virus - signals other nearby cells to enter a protective antiviral state |
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complement |
- group of enzymes that produce a cascade of reactions resulting in a variety of immune responses: lyse cells or opsinization or apoptosis - component of blood plasma - consists of several protein compounds - causes vasodilation - enhances phagocytosis |
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opsinization |
- mark cells for destruction by phagocytes |
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cluster designations (CD) |
- how subsets of lymphocytes are defined - surface markers that the cells carry |
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lymphocyte circulation |
- flow through the bloodstream, become distributed in tissues, return to the bloodstream - continuous recirculation |
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B Cells |
- antibody-mediated (humoral) immunity - morph into plasma cells and memory cells - under command of T cells - produce antibodies that attach pathogens |
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T cells |
- attack pathogens more directly - cell mediated immunity - go through the thymus before migrating to the lymph nodes and spleen - pre T cells develop into thymocytes |
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lymphocyte distribution |
- densest where they develop - bone marrow, thymus, lymph nodes, and spleen |
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activation of lymphocytes |
- require two stimuli: a specific antigen and activating chemicals |
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B Cell development |
- Pre-B cells develop by a few months of age - second stage occurs in lymph nodes and spleen - ancestors to antibody-secreting plasma cells |
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naive B cell activates |
after it binds to a specific antigen |
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antibodies |
- proteins (immunoglobins) secreted by activated B cells - "Y" shape - two heavy and two light polypeptide chains - has two antigen binding and two complement binding sites |
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IgM |
- main antibody - initial contact with antigen - naive B cells synthesize and insert into their own plasma membrane - activates complement, clumps cells |
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IgG |
- secondary antibody response - 75% of antibodies in the blood - binds to pathogens, activates complement, enhances phagocytosis by WBCs |
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IgA |
- mucous membranes, saliva, tears - prevents pathogens from attaching to epithelial cells in digestive and respiratory tract |
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IgE |
- allergies, worms - found on basophils in blood and mast cells in tissues - produces immediate allergic respons |
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IgD |
- small amount - on B cells signifying readiness |
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epitopes |
- bind to an antibody molecule's antigen binding site - forms an antigen-antibody complex that may produce several effects |
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alternative pathway |
- complement activation by innate immune mechanisms |
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compliment protein 3 |
- activated without antigen stimulation - produces full complement effect by binding to bacteria or viruses in presence of properdin |
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primary response of B cells |
- initial encounter with a specific antigen - triggers the formation and release of specific antibodies that reaches its peak in a few days |
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secondary response of B cells |
- a later encounter with the same antigen - triggers a quicker response - B memory cells rapidly divide - producing more plasma cells and thus more antibodies |
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clonal selection theory |
- body contains many diverse clones of cells - each cell is committed by its genes to synthesize a different antibody - when an antigen enters the body it selects the clone whose cells are synthesizing its antibody and stimulates them to proliferate and create more antibody - clones selected by antigens consist of lymphocytes and are selected according to the shape of antigen receptors on the lymphocytes plasm membrane - in B cells |
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activation of T cells |
- display antigens on their surface membranes that are similar to antibodies - activates when an APC presents an antigen that binds to its receptors - it then divides repeatedly to form a clone of identical T cells that differentiate into effector and memory T cells |
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effector T cells |
- go to site where antigen entered, binds to antigens, and begin attack |
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helper T cells |
- secrete cytokines that control the immune response - regulate the function of B and T cels, phagocytes, and other WBCs |
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cytotoxic T cells |
- release lymphotoxin to kill cells - kill virus infected and cancer cells |
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B Cells producs |
- plasma and memory cells |
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plasma cells produce |
antibodies |
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memory cells produce |
antibodies in a future attack |
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T cells produce |
- cytotoxic, helper, and memory T cells - regulate immune response |
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2 types of adaptive immunity |
- natural - artificial - may be active or passive |
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natural immunity |
- non deliberate exposure to antigens - getting sick |
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artificial immunity |
- results from deliberate exposure to antigens - immunization |
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active immunity |
- you make your own antibodies to an antigen - lasts longer |
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passive immunity |
- get antibodies from someone else - temporary but immediate |
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adaptive immunity stages |
- recognition of antigen - activation of lymphocytes - effector phase (immune attack) - decline of antigen - causes lymphocyte death to restore homeostasis - memory cells remain for later response if needed |
