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AP Biology Chapter 43 Flashcards

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5248865213Immune SystemThe totality of the body's physical barriers, immune cells, molecules, and physiological responses that enable you to block, fight, and destroy pathogens0
5248865214Innate ImmunityAll animals A defense that is active immediately upon infection and is the same whether or not the pathogen has been encountered before Nonspecific (less advanced, generic) Outer covering (skin/shell, chemical secretions, internal surfaces) Small preset group of receptor proteins bind to molecules/structures that are absent from animal bodies but common to viruses, bacteria, or other microbes Rapid Response1
5248865215Innate Immunity - Internal DefensesPhagocytic cells, Natural Killer cells, Antimicrobial Proteins, Inflammatory Reponse, Complement Protein Cascade Can have B and T cells2
5248865216Adaptive ImmunityVertebrates Only A defense that produces a a vast arsenal of receptors, each of which recognizes a feature typically found only on a particular part of a particular molecule in a particular pathogen Specific Slow development, slow response3
5248865217Adaptive Immunity - Internal DefensesAntibodies Cytotoxic cells (B and T Cells)4
5248865218Innate immunity of InvertebratesExoskeleton - First line Lysozyme - Breaks down bacterial cell walls Hemocytes - Phagocytosis or production of chemicals Antimicrobial Peptide secretion (disrupt plasma membranes)5
5248865219LysozymeAn enzyme that breaks down cell walls to protect insect digestive systems6
5248865220PhagocytosisThe cellular ingestion and digestion of bacteria and other foreign susbtances7
5248865221Innate Immunity of CertebratesCoexist with adaptive immunity Barrier defenses, phagocytosis, antimicrobial peptides (found in both vertebrates and invertebrates) Unique aspects to vertebrates (natural killer cells, interferons, inflammatory response)8
5248865222Barrier DefensesBlock entry of many pathogens Skin Mucous membrane Mucous Ciliated cells Saliva, tears, mucous (inhibits colonization, hostile lysozymes) pH from stomach Oil and sweat (pH 3-5) prevent growth9
5248865223Cellular Innate Defenses...10
5248865224Toll-Like Receptor (TLR)A mammalian receptor that binds to fragments of molecules characteristic of a set of pathogens After detection, a phagocytic cell engulfs them (traps in a vacuole) Lysosome fuses and degrades components)11
5248865225NeutrophilsOne main type of phagocytic cell in the mammalian body Attracted by signals from infected tissues Engulf and destroy infecting pathogens12
5248865226MacrophagesSecond main type of phagocytic cell in the mammalian body Larger than neutrophils Migratory or localized13
5248865227Dendritic CellsPopulate tissues (ex. skin) that ocntact the environment) Stimulate adaptive immunity against pathogens they encounter and engulf14
5248865228EosinophilsFound beneath mucosal surface Low phagocytic activity Important in defending against multicellular invaders (parasitic worms) Discharge destructive enzymes15
5248865229Natural Killer CellsUnique to vertebrates Circulate body to detect abnormal array of surface proteins (virus-infected or cancerous cells)16
5248865230InterferonsAntimicrobial proteins that provide innate defenses by interfering with viral infection Infected cells secrete interferons, which induce nearby uninfected cells to produce substances and inhibit viral reproduction Some white blood cells secrete interferons to activate macrophages17
5248865231Complement System (Protein Cascade)30 proteins that circulate blood plasma Inactive until activated by substances on the surface of many microbes Activation results in a cascade of biochemical reactions, lysis of invading cells Inflammation18
5248865232Inflammatory ResponseChanges brought about by signaling molecules released upon injury or infection that causes swelling (increased blood flow)19
5248865233HistamineInflammatory signaling molecule Released at sites of damage, dilates blood vessels, permeates blood vessels20
5248865234Mast CellsFound in connective tissue Stores histamine in granules (vesicles)21
5248865235CytokinesSignaling molecules that enhance immune response by promoting blood flow to the site of infection/injury Produced by macrophages and neutrophils22
5248865236InflammationCycles of signaling and response Activated complement proteins promote histamine release, attracting more phagocytic cells to enter infected tissues Enhanced blood flow delivers more antimicrobial peptides Pus accumulates (rich in white blood cells, dead pathogens, cell debris) Fever, meningitis, appendicitis, septic shock23
5248865237Evasion of Innate Immunity by pathogensOuter capsule interferes with molecular recognition Resist breakdown by lysosomes Hides from innate defenses24
5248865238LymphocytesWhite blood cells T and B cells25
5248865239ThymusAn organ in the thoracic cavity above the heart Lymphocytes mature into T Cells26
5248865240B CellsLymphocytes that mature from bone marrow27
52488652413rd Lymphocyte typeNatural Killer Remain in blood28
5248865242AntigenAny substance that elicits a response from a B Cell or T Cell29
5248865243Antigen ReceptorA protein that binds to an antigen30
5248865244EpitoteAn antigenic determinant The small, accessible portion of an antigen that binds to an antigen receptor Determines T/B cell specificity31
5248865245B-Cell Antigen ReceptorEach B cell antigen is Y-Shaped (four polypeptide chains - two identical heavy chains, two identical light chains, with disulfide bridges) Transmembrane region near one end of a heavy chain anchors the receptor in the cell's plasma membrane) Short tail region at the end of the heavy chain extends into cytoplasma Variable regions bind to antigens (constant regions make up the rest) Bind to intact epitotes of intact antigens circulating in body fluids32
5248865246Variable RegionsAmino Acid sequence varies extensively from one B cell to another Specific binding33
5248865247Antibody/Immunoglobulin (Ig)A protein secreted when an antigen receptor binds to an antigen Y-Shaped organization May bind to antigens on surface of pathogens or free in body fluids34
5248865248T Cell Antigen ReceptorTwo different polypeptide chains (Alpha and Beta chain) linked by a disulfide bridge Transmembrane region anchors the receptor to plasma membrane Outer tip - Variable region Only bind to fragments of antigens displayed on the surface of host cells35
5248865249MHC (Major Histocompatibility Complex) MoleculeA host protein that displays the antigen gragment on the cell surface36
5248865250Antigen PresentationThe display of the antigen fragment in an exposed groove of the MHC protein Pathogen or part of a pathogen is taken in by a host cell Enzymes cleave the antigen into smaller peptides (antigen fragments) MHC binds to fragments MHC moves to surface and presents antigen37
5248865251B Cell and T Cell developmentDiversit, self tolerance (lack of reactivity to self), cell proliferation, stronger secondary response38
5248865252Generation of B and T Cell DiversityEach person makes more than 1 mil diff. B Cell antigen receptors and 10 mil. different T Cell antigen receptors Recombinase enzyme linkas a light chain V gene seg. to one J (joining) seg. to form a single exon Rnadomly links any one of 40 V to any one of 5 J39
5248865253Origin of Self ToleranceLymphocyte antigen receptors are tested for self-reactivity Those that are self reactive undergo apoptosis or rendered nonfunctional40
5248865254Proliferation of B and T Cells; Clonal SelectionBinding of antigen receptor to epitote activates lymphocyte B/T cell then undergoes multiple cell divisions to produce clones41
5248865255Effector CellsShort lived cells that take effect immediately against the antigen or any pathogen producing that sntigen42
5248865256Memory CellsLong-lived cells that can give rise to effector cells if the same antigen is encountered later in the animal's life43
5248865257Primary Immune ResponsePeaks 10-17 days after initial exposure Selected B and T cells give rise to effector and memory forms44
5248865258Secondary Immune ResponseHallmark of adaptive immunity Peaks 2-7 days after exposure Faster, stronger, longer response Relies on reservoir of memory T and B cells generated following the initial exposure45
5248865259Humoral Immune ResponseOccurs in blood/lymph Antibodies help neutralize or eliminate toxins and pathogens in blood/lymph46
5248865260Cell-Mediated immune responseSpecialized T cells destroy infected host cells47
5248865261Helper T-CellTriggers both humoral and cell-mediated immune response Do not carry out the responses themselves Signals the production of antibodies To activate adaptive immune responses, a foreign molecule must be present that can bind specifically to the antigen receptor of the T Cell AND the antigen must be displayed on the surface of an antigen-presenting cell48
5248865262Antigen-Presenting CellA dendritic cell, macrophage, or B Cell49
5248865263What distinguishes an antigen-presenting cell?Antigen-Presenting Cells can also be host cells Class I MHC - Body Cells Class I and Class II MHC - Antigen presenting cells Class II allows antigen presenting cells to be recognized50
5248865264Helper T/Antigen-Presenting Cell InteractionAntigen receptors on Helper T surface bind to specific epitote of an antigen frag. Accessory protein on helper T Cell attaches to Class II MHC (keeps them joined) Signals from cytokines are exchanges (antigen-presenting cell secrete cytokines to stimulate Helpter T, causing the Helpter T to produce cytokines) Helper T Cell proliferates (forms Activated Helpter T Cells) to stimulate cytotoxic T Cells B Cells present antigents to already activated helper T cells, which activates B Cells themselves51
5248865265Cytotoxic T CellsCell-mediated immune response effector cells Requires signaling molecules from helper T and the interaction with a antigen-presenting cell to activate Frag. of foreign proteins produced in infected host cells associate with Class I MHC (recognized by cytotoxic T) Secrete proteins that disrupt membrane integrity and tirgger apoptosis Deprives pathogen of reproduction host and exposes them to antibodies52
5248865266Activation of B CellsActivation by antigen is aided by cytokine (secreted by helper T) Stimulated by antigen and cytokines, B Cells proliferate into memory and effector/plasma cells (secrete antibodies)53
5248865267Antigen processing and display in B CellsPresents only the antigen to which it specifically binds (magrophages/dendritic cells present fragments from a wide variety of protein antigens) Antigen binds to receptor on B Cell surface Receptor-mediated endocytosis, class II MHC protein then presents antigen frag to helpter T54
5248865268B Cell ActivationCell-to-cell contact between B cell and Helper T Cell 1000's of plasma cells produced (these stop expressing a membrane bound antigen receptor) and produce/secrete antibodies (2000/sec for 4-5 days) Antigens recognized by B cells contain multiple epitotes (single antigen, variety of B cells activated)55
5248865269Antibody FunctionBinds to entigens, marks pathogens for inactivation/destruction56
5248865270Antibody Function - NeutralizationAntibodies bind to viral surface proteins Prevent infection of host cell, or recruits natural killer Bind to toxins released in body and prevent entrance57
5248865271Antibody Function - OpsonizationAntibodies bound to antigens on bacteria present a readily recognized structure for macrophages or neutrophils Increase phagocytosis May link bacterial cells, virus particles, or other foreign substances into aggregates (each antibody has 2 binding sites) Positive feedback (antibodies increase phagocytosis, phagocytic cells present antigens, more B cells formed, more antibodies released)58
5248865272Antibody Function - Membrane Attack ComplexComplement protein binds to antigen-antibody complex on a foreign cell (or enveloped virus) Complement system activates next protein Activated complement protein cascade generates membrane attack complex (forms pores in membrane of foreign cells, ions/water rush in, lysis)59
5248865273Active ImmunityDefenses that arise when a pathogen infects the body and prompts a primary or secondary immune response60
5248865274Passive ImmunityAntibodies provided by mother guard against pathogens that have never infected the newborn61
5248865275Immunization/VaccinationIntroduction of antigens into the body used to induce adaptive immunity Antibodies from an immune animal are injected into nonimmune animal (artificial passive immunization)62
5248865276Monoclonial AntibodiesAntibodies prepared from a single blone of B cells grown in a culture63
5248865277Immune RejectionAntigen receptors are not self-tolerant of a recipient's body cells (Immune system is health)64
5248865278Blood GroupsType A - A Carbohydrate, Anti-B Type B - B Carbohydrate, Anti-A Type AB - Both A and B carbohydrate, no antibody Type O - Neither, Anti-A and Anti-B65
5248865279Tissue and Organ TransplantsMHC stimulate immune response Diversity of MHC66
5248865280AllergiesExaggerated (hypersentive) responses to certain antigens (allergens)67
5248865281Autoimmune DiseaseImmune system is active against particular molecules of the body Immune system is self-reactive Lupus - Antibodies vs histones and DNA (breakdown of body cells - skin rashes, fevers, arthritis, kidney dysfunction) Rheumatoid Arthritis - Damage and inflammation of joints/cartilage Type I Diabetes Mellitus - Insulin producing Beta cells of pancreas are destroyed by cytotoxic T Cells Multiple sclerosis - T cells infiltrate central nervous system and destroy myelin sheath68
5248865282ImmunodeficiencyAn immune system response to antigens that is defective or absent69
5248865283Aquired Immunodeficiency SyndromeHIV virus70
5248865284Antigenic VariationChanges in epitote expression Lessens recognition by immune system71
5248865285LatencyViruses enter an inactive state No proteins made, no free virus particles, adaptive immunity is not triggered72
5248865286HIVInfects helper T Cells, high mutation (antigenic variation)73
5248865287CancerCancer frequency increases dramatically when adaptive immunity is inactivated74

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