Chapter 43

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Chapter 43
2011-04-10 16:42:38
Bio II

Midterm 2
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  1. pathogen
    infectious agents that cause disease; bacteria, viruses, protists and fungi
  2. barrier
    animal's most basic defense against a pathogen
  3. innate immunity
    found in all animals; active immediately upon infection and are the same whether or not the pathogen has been previously encountered; ex: barrier defenses
  4. acquired immunity
    second defense system found only in vertebrates; activated after innate immune defenses take effect; develops more slowly and works better the second time around
  5. mucus
    viscous fluid that enhances defenses by trapping microbes and other particles
  6. Toll-like receptors (TLR)
    recognize fragments of molecules characteristic of a set of pathogens
  7. neutrophils
    engulf and destroy microbes intracellularly by enzymes (phagocytic); attracted by signals from infected tissues; most abundant phagocytic cells in mammalian body, found in blood, extracellular fluid and peripheral lymphoid tissues
  8. macrophages (monocytes)
    also engulf and destroy microbes intracellularly by enzymes (phagocytic); also found in blood, extracellular fluid and peripheral lymphoid tissues
  9. eosinophils
    type of phagocyte but has low phagocytic activity; defends against parasitic worms (multicellular invaders) by discharging enzymes that destroy the invader and consume antibody-antigen complexes
  10. dendritic cells
    found in tissues in direct contact with environment; stimulate development of acquired immunity (a monocyte that has left the blood?)
  11. interferons
    proteins secreted by body cells infected by a virus; provide innate defense against infections because they induce nearby uninfected cells to produce substances that INHIBIT viral reproduction
  12. injury or infection causes _________ (in blood) and ____ _____ (from connection tissue) to be release
    basophils; mast cells
  13. histamine
    important signaling molecule that causes inflammation; released by both mast cells and basophils; release causes blood vessels to dilate and become more permeable so antimicrobial proteins can be delivered to infection site
  14. mast cells
    connective tissue cells that store chemicals in granules for secretion
  15. natural killer (NK) cells
    recognize and eliminate diseased cells (those that fail to exhibit class I MHC protein, cancerous) by secreting proteins that lead to cell death
  16. T cells
    lymphocyte (WBC) that originates from stem cells in bone marrow but migrate to thymus; component of the ACQUIRED immune response
  17. B cells
    lymphocyte (WBC) that originates from stem cells in bone marrow and stays there to mature; part of the ACQUIRED immune response
  18. cytokines
    proteins secreted by phagocytic cells (macrophages/dendritic cells, aka part of the innate immune response) that help recruit and activate lymphocytes
  19. antigen
    any foreign molecule that is specifically recognized by lymphocytes and elicits a response from them; most are large proteins or polysaccharides; some can be secreted into extracellular fluid (like bacterial toxins) while others may protrude from surface of pathogens/foreign cells
  20. antigen receptor
    receptors [are about 1,000] in B & T cells plasma membrane; B cells sometimes give rise to plasma cells (aka cells that secrete a soluble form of antigen receptor); SECRETED protein is called an antibody/immunoglobin (think body is what comes from the body)
  21. epitome
    the small portion of the antigen that's recognized by B & T cells' antigen receptors
  22. cytotoxic T cells
    subgroup of T cells that recognize class I MHC molecules that display bound antigen fragments; they use toxic gene products to kill infected cells
  23. Class II MHC molecules
    molecules that bind to antigen fragments that have already been digested through phagocytosis or endocytosis [internalized antigens]; only produced by antigen-presenting cells (aka dendritic cells, macrophages & B cells)
  24. helper T cells
    group of T cells that assist both B cells and cytotoxic T cells; antigen-presenting cells show helper T cells as well as cytotoxic T cells antigens to help aid in the process of destruction
  25. effector cells
    created from the cloning of activated B or T cells; are short lived and attack the antigen or any pathogen producing said antigen
  26. memory cells
    created from the cloning of activated B or T cells; long-lived (but less numerous) cells that bear receptors for specific antigens
  27. clonal selection
    the proliferation of a lymphocyte into a clone of cells in response to binding an antigen
  28. primary immune response
    the production of effector cells from a clone of lymphocytes during the first exposure to an antigen; peaks about 10-17 days after initial exposure
  29. secondary immune response
    a faster, longer lasting, and larger response that occurs after an individual has been exposed to the same antigen; shown in the larger amount of antibodies present in a shorter amount of time for this response than for a primary response
  30. humoral immune response (antibody-mediated response)
    involves the activation and clonal selection of effector B cells which secrete antibodies (proteins) that circulate in the blood and lymph (body fluids); defends mostly against germs outside cells (extracellular germs)
  31. cell-mediated immune response
    predominant; involves the activation of clonal selection of cytoxic T cells which identify and destroy the target cells; antibodies aren't secreted, cells are just told what to do; response defends mostly against intracellular pathogens, transplanted tissues, cancerous cells; helper T cells aid in both types of responses
  32. anaphylactic shock causes:
    dilation of peripheral blood vessels cause a precipitous drop in blood pressure; epi pen = epinephrine, which counteracts this allergic response