BIOL40C Ch. 22 Lymphatic System & Immunity

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BIOL40C Ch. 22 Lymphatic System & Immunity
2012-06-02 08:42:11
Lymphatic System Immunity

Lymphatic System & Immunity
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  1. immunity
    type of resistance that involves activation of specific lymphocytes that combat a foreign substance
  2. resistance
    the ability to ward off the pathogens that produce disease
  3. susceptibility
    lack of resistance
  4. DEF'N: lymphatic system
    body system that carries out immune responses
  5. non-specific (innate) immunity
    general defense mechanisms effective on a wide range of pathogens
  6. specific (adaptive) immunity
    ability to fight a specific pathogen
  7. 2 types of specific immunity
    • 1) cell-mediated immunity
    • 2) antibody-mediated immunity
  8. lymph
    fluid flowing within lymphatic vessels
  9. Where are lymphocytes produced?
    bone marrow
  10. 3 functions of the lymphatic system
    • 1) draining excess interstitial fluid/plasma proteins from tissue spaces
    • 2) transporting dietary lipids/vitamins from GI tract to blood
    • 3) facilitating immune responses (recognize foreign substances)
  11. 4 primary lymphatic organs
    • 1) red bone marrow
    • 2) thymus
    • 3) spleen
    • 4) lymph nodes
  12. 3 secondary lymphatic organs
    • 1) tonsils
    • 2) adenoids
    • 3) MALT
  13. how lymphatic vessels differ from blood vessels
    • 1) larger in diameter
    • 2) one-way structure (interstitial fluid can flow in, but not out)
    • 3) overlapping endothelial cells
  14. lacteals
    • lymphatic capillary in the villus of the small intestine;
    • functions to transport fats from small intestine into blood
  15. 2 major lymphatic ducts
    • 1) thoracic duct
    • 2) right lymphatic duct
  16. 3 parts of the body the thoracic duct drains
    • 1) left side of the head, neck, and chest
    • 2) left upper extremity
    • 3) entire body below ribs
  17. parts of the body the right lymphatic duct drains
    upper right side of the body
  18. Where is the thymus gland located?
  19. 2 types of cells found in the thymic cortex
    • 1) T lymphocytes
    • 2) macrophages
  20. 2 types of cells found in the thymic medulla
    • 1) reticular epithelial cells (produce thymic hormones)
    • 2) Hassall's corpuscles (T cell death site)
  21. Hassall's corpuscles
    clusters of concentric layers of epithelial cells in the thymic medulla that are the possible site of T cell death
  22. Major function of thymus
    location of T cell maturation
  23. Difference in size and function of a thymus in a newborn vs. an adult
    • larger in infants (70g vs. 3g)
    • before atrophy, populates secondary lymphatic organs/tissues with T cells
  24. lymph node structure
    • bean shaped
    • dense connective tissue capsule extends into node
    • supporting network of reticular fibers & fibroblasts internal to capsule
  25. function of lymph nodes
    • filters lymph
    • foreign substances trapped by reticular fibers
  26. parenchyma of lymph node
    functioning part of lymph node
  27. What is found in the white pulp?
    lymphatic tissue (lymphocytes, macrophages) around branches of splenic artery
  28. What is found in the red pulp?
    venous sinuses filled with blood and splenic cords (RBCs, macrophages, lymphocytes, plasma cells, granulocytes)
  29. 2 components of splenic parenchyma
    • 1) white pulp
    • 2) red pulp
  30. What role does the spleen play in pregnancy?
    red pulp is involved in the production of blood cells during this time
  31. trabeculae
    capsular extensions that divide the lymph nodes into compartments, and provide support and a route for blood vessels into the interior of a node
  32. Where is MALT found?
    throughout connective tissue of mucous membranes (no capsule)
  33. Where are the tonsils?
    ring at top of throat
  34. Where is the appendix?
  35. metastasis
    spread of disease from one part of the body to another
  36. How does a tumor metastasize?
    cancer cells travel via blood/lymphatic system and establish new tumors where they lodge
  37. methods of mechanical innate immunity
    • 1) skin closely packed
    • 2) mucous membranes trap/move microbes
    • 3) washing action of tears, urine, saliva
  38. methods of chemical innate immunity
    • 1) sebum inhibits growth
    • 2) perspiration lysozymes
    • 3) acidic pH of gastric juice, vaginal secretions
  39. 3 antimicrobial proteins
    • 1) interferons
    • 2) complement
    • 3) defensins
  40. IFNs
    • interferons;
    • induce synthesis of antiviral proteins that interfere with viral replication
  41. complement
    • enhance certain immune reactions
    • cause cytolysis of microbes, promotes phagocytosis, and contributes to inflammation
  42. natural killer cells
    • kill microbes and tumor cells
    • attack cells displaying abnormal MHC antigens
  43. 2 phagocytic cells
    • 1) neutrophils
    • 2) macrophages
  44. 5 phases of phagocytosis
    • 1) chemotaxis
    • 2) adherence
    • 3) ingestion
    • 4) digestion
    • 5) killing
  45. 4 methods of evasion of phagocytes by microbes
    • 1) capsule formation
    • 2) toxin production
    • 3) interference with lysozyme secretion
    • 4) ability to counter oxidants produced by phagocytes
  46. 2 functions of inflammation
    • 1) trap foreign material
    • 2) begin tissue repair
  47. 5 clinical signs of inflammation
    • 1) redness
    • 2) heat
    • 3) swelling
    • 4) pain
    • (5) loss of function
  48. 3 stages of inflammation
    • 1) vasodilation/increased permeability of blood vessels
    • 2) phagocyte migration
    • 3) tissue repair
  49. abscess
    accumulation of pus in a confined space
  50. ulcer
    open sore
  51. fever
    • abnormally high T that occurs because the hypothalamic thermostat is reset
    • intensifies effects of interferons, inhibits bacterial growth, speeds up tissue repair
  52. cytokine that is major inducer of fever
    IL-1 (interleukin 1)
  53. specificity
    recognition of self & non-self
  54. memory
    2nd encounter produces more vigorous response
  55. antigen
    substances recognized as foreign by the immune responses
  56. Where are pre-T cells formed?
    stem cells in bone marrow
  57. Where do T cells mature?
  58. types of invaders are T cells most able to combat
    • fungi
    • viruses
    • parasites
    • cancer
    • tissue transplants
  59. Where do B cells develop?
    bone marrow
  60. type of invader B cells are most able to combat
  61. epitope
    small part of the antigen that triggers an immune response
  62. hapten
    • smaller than antigen
    • can't trigger immune response unless attached to body protein
  63. 2 major characteristics of antigens
    • 1) immunogenicity (ability to provoke immune response)
    • 2) reactivity (ability to react to cells/Ab's it caused to be formed)
  64. Why can the immune system recognize and respond to so many different epitopes?
    cells have a great diversity of receptors due to genetic recombination
  65. MHC antigen
    • major histocompatibility complex
    • molecules that are unique surface markers on all nucleated cells
  66. MHC-I molecules
    built into cell membrane of all cells except RBCs

    endogenous antigen by an infected body cell

  67. MHC-II molecules
    only on membrane of APCs (macrophages, B cells, thymus cells)

    exogenous antigen by an APC

  68. function of MHC antigens
    help a T cell recognize whether something is foreign
  69. histocompatibility testing
    tests similarity of MHC antigens on body cells of different individuals

    for tissue typing and IDing biological parents
  70. 3 cells types of APCs
    • 1) macrophages
    • 2) B cells
    • 3) dendritic cells
  71. cytokine
    small local mediator proteins involved in immune response

    mostly secreted by lymphocytes and APCs
  72. interleukin
    costimulates proliferation of T and B cells
  73. interferon
    activates macrophages, NK cells
  74. IL-2
    cytokine most important in costimulation of proliferation of helper T cells, cytotoxic T cells, and B cells

    activates NK cells
  75. -interferon
    strongly stimulates phagocytosis by neutrophils and macrophages

    activates NK cells
  76. lymphocyte important in cell-mediated immunity
    T cell
  77. cytotoxic T cell
    • from CD8+ T cells
    • recognize foreign antigens combined with MHC-I molecules on surface of infected body cells, some tumor cells, cells of tissue transplant
  78. helper T cell
    • from CD4+ T cells
    • recognize exogenous antigens associated with MHC-II molecules on the surface of APCs
    • costimulates lymphocytes (secretes IL-2)
  79. memory T cell
    • don't attack infected body cells
    • can quickly proliferate/differentiate into active T cells and more memory T cells if the same ag enters in the future
  80. 3 steps in activation, proliferation, differentiation of CD8 (cytotoxic) T cells
    • 1) receptor binds to foreign part of MHC-I complex (on infected cell)
    • 2) costimulation by IL-2 from helper T cell results in proliferation of CD8 cells
    • 3) CD8 T cells proliferate/differentiate into Tc cells and memory Tc cells
  81. 3 steps in activation, proliferation, differentiation of CD4 (helper) T cells
    • 1) inactive helper T cell receptor binds to foreign part of MHC-II (on APC) & becomes activated
    • 2) activated cells produce IL-2 (costimulator)
    • 3) Th cell proliferates/differentiates into Th cells and memory Th cells
  82. 3 methods of cytotoxic (CD8+) T cell attack
    • 1) secretion of granules containing perforin and granulysin
    • 2) secretion of lymphotoxin that activates enzymes in the target cell resulting in DNA fragmentation
    • 3) secretion of (gamma)interferon stimulates macrophages to phagocytose
  83. immunological surveillance
    immune system finds, recognizes, & destroys cells with tumor antigens

    not effective in destroying types of tumors caused by viruses
  84. lymphocyte responsible for antibody-mediated immunity
    B cells
  85. Where in the lymphatic system does antigen come in contact with B cells?
    in lymph nodes, spleen, Peyer's patches
  86. plasma cells
    B cells after they have differentiated into antibody-secreting cells
  87. steps in activation, proliferation, differentiation of B cells
    • 1) antigen on microbe binds to B cell receptors
    • 2) antigen is taken into B cell, broken down, and moved to cell membrane
    • 3) helper T cells recognize Ag-MHC-II complex & secretes IL-2 to costimulate B cell
    • 4) B cell proliferates/differentiates into plasma cells and memory B cells
    • 5) plasma cells enter circulation
  88. IgG antibody structure
    • 4 polypeptide chains
    • -heavy and light chains
    • -variable (tips of H&L) and constant portions
    • monomer
    • Y shaped
  89. 5 different classes of antibodies
    IgG, IgA, IgM, IgD, IgE
  90. IgG function
    protects against viruses and bacteria
  91. IgA function
    localized protection of mucous membranes against viruses/bacteria
  92. IgM function
    • activates complement
    • causes agglutination and lysis of microbes
    • antigen receptors on B cells

    ABO antibodies
  93. IgD function
    activation of B cells
  94. IgE function
    • allergic/hypersensitivity reactions
    • protection against parasitic worms
  95. monoclonal antibody
    clone of plasma cells that recognize just 1 epitope
  96. How are monoclonal antibodies produced?
    fusing B cells with tumor cells (hybridoma) and culturing them
  97. 4 types of hypersensitivity
    • I) anaphylaxis
    • II) cytotoxic
    • III) immune complex
    • IV) cell-mediated
  98. Type I hypersensitivity
    • anaphylaxis
    • most common
    • interaction of allergens with IgE Abs of mast cells&basophils
  99. Type II hypersensitivity
    • cytotoxic
    • reactions by IgG or IgM against blood/tissue cells
    • results in complement activation
    • incompatible blood
  100. Type III hypersensitivity
    • immune complex
    • involve antigens, IgA or IgM, and complement
    • most autoimmune diseases
  101. Type IV hypersensitivity
    • cell mediated/delayed hypersensitivity
    • allergens are taken up by APCs that migrate to lymph and present allergen to T cells
    • intracellular bacteria, some allergens (poison ivy)