A&P 2

Card Set Information

A&P 2
2010-11-03 13:36:06
Immune system

Immune System
Show Answers:

  1. What are the two intrinsic systems of the immune system?
    • innate (nonspecific) defense system
    • adaptive (specific) defense system
  2. What are the two lines of defense for the innate system?
    • External body membranes (skin and mucosae)
    • Antimicrobial proteins, phagocytes and other cells
  3. What is the most important mechanism of the secondary innate defense system?
  4. Adaptive defense system takes-
    longer to react than the innate system
  5. Adaptive defense system is the _________ and attacts ________________
    third line of defense, particular foreign substances
  6. Internal defenses of the innate defense system include
    • Phagocytes
    • Natural killer cells
    • inflammation
    • antimicrobial proteins
    • fever
  7. Adaptive defenses include
    • humoral immunity-B Cells
    • Cellular immunity-T Cells
  8. Keratin (a protein in the skin) is resistant to
    weak acids and bases, bacterial enzymes and toxins
  9. What are 5 surface barrier chemicals?
    • Skin acidity
    • Lipids in sebum and dermcidin in sweat
    • HCI and ptrotein-digesting enzymes of stomach mucosae
    • Lysozyme of saliva and lacrimal fluid (tears)
    • Mucus
  10. What are respiratory modifications of suface barrier defense systems?
    • Mucos-coated haris in the nose
    • Cilia od upper respiratory tract sweep dust-and bacteria-laden mucus from lower respiratory passages.
  11. Macrophages develop from _____________ to become the ____________________
    monocytes, chief phagocytic cells
  12. What are the two types of macrophages?
    • Free macrophages that wander through tissue (e.g. alveolar macrophages)
    • Fixed macrophages are permanent residents of some organs (e.g. Kupffer cells (liver) and microglia (brain))
  13. Neutrophils become phagocytic on ________________________
    encountering infectious material in tissues
  14. The first step of phagocytosis is __________________ which is facillitated by ______________
    adherence of phagocyte to pathogen, opsonization-coating of pathogen by complent proteins or antibodies
  15. What is the second event of phagocytosis?
    Phagocyte forms pseudopods that eventually engulf the particles forming a phagosome
  16. What is the third event of phagocytosis?
    Lysosome fuses with the phagocytic vesicle, forming a phagolysosome
  17. What is the fourth event of phagocytosis?
    Lysosomal enzymes digest the particles, leaving a residual body.
  18. What is the fifth event of phagocytosis?
    Exocytosis of the vesicle removes indigestible and residual material
  19. How do phagocytes destroy pathogens?
    • By adicification and digestion by lysosomal enzymes
    • Respiratory burst: release of cell killing free radicals and activation of additional enzymes
    • Oxiding chemicals (e.g. H202)
    • Defensins (in neutrophils)
  20. Natural killer cells are
    • Large granular lymphocytes
    • Target cells that lack "self" cell-surface receptors
    • Induce apoptosis (programmed cell death) in cancer cells and virus-infected cells
    • Secrete potent chemicals that enhance the inflammatory response
  21. What are the 4 aspects of the imflammatory response?
    • Triggered whenever body tissues are injured or infected
    • Prevents the spread of damaging agents
    • Disposes of cell debris and pathogens
    • Sets the stage for repair
  22. What are the cardinal signs of acute inflammation?
    • Redness
    • Heat
    • Swelling
    • Pain
    • (and sometimes 5. impairment of function)
  23. In the inflammatory response macrophages and epithelial cells of boundary tissues bear _______________
    Toll-like receptors (TRL's)
  24. TRLs recognize
    specific classes of infecting microbes
  25. Activated TRLs trigger
    the release of cytokines that promote inflammation
  26. The inflammatory mediators (promote inflammation) are
    • Histamine (from mast cells)
    • Blood proteins
    • Kinins, prostaglandins (PGs), leukotrienes, and complement (released by injured tissues, phagocytes, lymphocytes, basophils, and mast cells)
  27. Inflammatory chemicals cause
    • Dilation of arterioles, resulting from hyperemia
    • Increased permeability of local capillaries and edema (leakage or exudate)
  28. Exudate contains
    proteins, cloting factors, and antibodies
  29. What are the functions of the surge of exudate during the inflammatory response?
    • Moves foreign material into lymphatic vessels
    • Delivers clotting proteins to form a scaffold for repair and to isolate the area
  30. Neutrophils, then ___________ flood to inflamed sites
  31. What is the first event in the internal defense response?
    Leukocytosis: neutrophils enter blood from bone marrow
  32. What is the second event of the internal defense response?
    Margination: Neutrophils cling to capillary wall
  33. What is the third event of the internal defense system?
    Diapededis: Netrophils flatten and squeeze out of capillaries
  34. What is the fourth event of the internal defense system?
    Chemotaxis: Neutrophils follow chemical trail
  35. Interferons (IFNs) and complement proteins are
    antimicrobial proteins
  36. Interferons and complement proteins attack __________ and hinder _______________
    microorganisms directly, microorganisms ability to reproduce
  37. Viral-infected cells are activated to
    secrete IFNs
  38. IFNs enter neighboring cells, these cells produce
    antipviral proteins that block viral reproduction
  39. Interferons are produced by a variety of body cells:
    • Lymphocytes produce gamma or immune interferon
    • Most other WBCs produce alpha interferon
    • Fibroblasts produce beta interfuron
  40. Interferons activate
    macrophages and mobilize NKs
  41. Inteferon functions are
    • anti-viral
    • reduce inflammation
    • activvate macrophages and mobilize NKs
  42. What are the two types of genetically engineered IFNs for?
    • Antiviral agents against hepatitis and genital warts virus
    • Multiple sclerosis treatment
  43. Complement is
    major mechanism for destroying foreign substances
  44. Complement is about
    20 blood proteins that circulate in an inactive form
  45. Complement includes
    C1-C9, factors B, D, and P, and regulatory proteins
  46. Complement amplifies _______________
    kills _____________
    enhances __________________
    all aspects of the inflammatory response; bacteria and certain other cell types by cell lysis; both nonspecific and specific defenses
  47. What are the two pathways of complement activation?
    • Classical pathway
    • Alternative pathway
  48. During the complement activation classical pathway
    • Antibodies bind to invading organisms
    • C1 binds to the antigen-antibody complexes (complement fixation)
  49. During complement activation alternative pathway
    triggered when activated C3, B, D, and P interact on the surface of microorganisms
  50. Each pathway of complement activation involves
    • activationof proteins in an orderly sequence
    • each step catalyzes the next
    • both pathways converge on C3, which cleaves into C3a and C3b
  51. Activated complement enhances___________, promotes _______ and causes_________
    • inflammation
    • phagocytosis
    • cell lysis
  52. Fever is the
    systemic response to invading organisms
  53. Leukocytes and macrophages exposed to foreign substances secrete
  54. Pyrogens reset
    the body's thermostat upward
  55. High fevers are dangerous because
    heat denatures enzymes
  56. What are the benefits of moderate fever?
    • Causes the liver and spleen to sequester iron and zinc (needed for microorganisms)
    • Increases metabolic rate, which speeds up repair
  57. The adaptive immune (specific defense) system protects against _____________, amplfies ____________ and activates ________________
    • infectious agents and abnormal body cells
    • the inflammatory response
    • complement
  58. Adaptive immune response is _________, is ____________, and has _____________
    • specific
    • systemic
    • memory
  59. What are the two overlapping arms of the adaptive defense system?
    • Humoral (antibody-mediated) immunity
    • Cellular (cell-mediated) immunity
  60. What are antigens?
    • Substances that can mobilize the adaptive defenses and provoke an immune response
    • Most are large, complex molecules not normally found in the body (nonself)
  61. What are the important functional properties of antigens?
    • Immunogenicity
    • Reactivity
  62. What is immunogenicity?
    Ability to stimulate proliferation of specific lymphocytes and antibodies
  63. What is reactivity?
    Ability to react with products of activated lymphocytes and antibodies released
  64. What are examples of complete antigens?
    Foreign protein, polysaccharides, lipids, and nucleic acids
  65. Haptens are
    Small molecules (peptides, nucleotides, and hormones)
  66. Haptens are not
    immunogenic by themselves. They must be attached to body proteins
  67. What are examples of haptens?
    poinson ivy, animal dander, detergents and cosmetics
  68. Antigenic determinants are certain
    parts of an entire antigen that are immunogenic. Antibodies and lymphocyte receptors bind to them.
  69. Most naturally occurring antigens haave
    numerous antigenic determinants that mobilize several different lymphocyte populations and form different kinds of antibodies against it.
  70. Self-Antigens are
    protein molecules on the surface of cells
  71. An example of self-antigens are
    • MHC proteins
    • Coded for by genes of the major histocompatability complex (MHC) and are unique to an individual
  72. What are the two classes of MHC proteins?
    • Class I MHC proteins, found on virtually all body cells
    • Class II MHC proteins, found on certain cells in the immune response
  73. MHC proteins display
    peptides (usually self-antigens)
  74. Ininfected cells,MHC proteins display
    fragments of foreign antigens, which help mobilize
  75. What are the cells of the adaptive immune system?
    • B lymphocytes (humoral immunity)
    • T lymphocytes (cell-mediated immunity)
    • Antigen presenting cells (APCs)
  76. APCs do not ________________, they play ________________
    • respond to specific antigens
    • essential auxillary roles in immunity
  77. Lymphocytes originate in
    red bone marrow
  78. B cells mature in ________________
    T cells mature in ________________
    • red bone marrow
    • the thymus
  79. When mature, lymphocytes have
    • immunocompetence: they are ale to recognize and bind to a specific antigen
    • Self-tolerance-unresponsice to self antigens
  80. Naive (unexposed) B and T cells are exported to
    lymph nodes, spleen, and other lymphoid organs
  81. T cells mature in the thymus under
    negative and positive selection pressures
  82. Positive selection selects T cells that are
    capable of binding to self-MHC proteins (MHC restriction)
  83. Negative selection prompts
    apoptosis of T cells that bind to self-antigens diplayed by self-MHC
  84. Self-reactive B cells are _________________, or undergo _____________ and are inactivated if ____________
    • eliminated by apoptosis (deletion)
    • receptor editing-rearrangement of their receptors
    • (anergy) if they escape from the bone marrow
  85. Lymphocytes make up
    to a billion types of antigen receptors
  86. Genes determine which
    foreign substances the immune system will recognize and resist
  87. APCs engulf _____________, present ______________________
    • antigens
    • fragments of antigens to be recognized by T cells
  88. What are the major types of antigen-presenting cells?
    • Dendritic cells in connective tissues and epidermis
    • Macrophages in connective tissues and lymphoid organs
    • B cells
  89. Macrophages and dendritic cells present _________ and activate ___________
    • antigens
    • T cells
  90. Macrophages mostly remain
    fixed in the lympoid organs
  91. Dendritic cells internalize
    pathogens and enter lymphatics to present the antigens to T cells in lymphoid organs
  92. Activated T cells release chemical that
    prod macrophages to become instaiable phagocytes and to secrete bactericidal chemicals
  93. The adaptive immunity uses
    lymphocytes, APCs, and specific molecules to identify and destroy nonself substances
  94. The adaptive immunity depends on the ability of its cells to
    • recognize antigens by binding to them
    • communicate with one another so that the whole system mounts a specific response
  95. When lymphocytes are mature they have tw things
    • immunocompetance: they are able to recognize and bind to a specific antigen
    • Self-tolerance:unresponsive to self-antigens
  96. ___________________ B and T cells are exported to lymch nodes, spleen, and other lymphoid organs
    Naive (unexposed)
  97. T cells mature in _________ under _______________________ controls
    • the thymus
    • negative and postive selection presssures
  98. Selects T cells capable of binding to self-MHC proteins (MHC restriction) describes
    T cells positive selection
  99. Prompts apoptosis of T cells that bind to self-antigens displayed by self-MHC
    Ensures self-tolerance describes
    T cells negative selection
  100. B cells mature in
    red bone marrow
  101. Self-reactive B cells are eliminated by ________ or undergo ________________, are
    • apoptosis (clonal deletion)
    • receptor editing - rearangement of their receptors
    • inactivated (anergy) if they escape from the bone marrow
  102. Lymphocytes make up to ______________________ which are
    • a billion different types of antigen receptors
    • coded for by about 25,000 genes
  103. Genes determine which
    foreign substances the immune system will recognize and resist
  104. Antigen presenting cells (APCs) engulf ____________, present _________________ to be recognized by _____________
    • antigens
    • fragments of antigens
    • T cells
  105. What are the major types of APCs?
    • Dendritic cells in cconnective tissue and epidermis
    • Macrophages in connective tissues and lymphoid organs
    • B cells
  106. Macrophages and dendritic cells present
    antigens and activate T cells
  107. what cells remain mostly fixed in lymphoid organs?
  108. What cells internalize pathogens and enter lyphatics to present the antigens to T cells in lymphoid organs?
    dendritic cells
  109. An antigen challenge is
    the first encounter between an antigen and a naive immunocompetent lymphocyte
  110. An antigen challenge usually occurrs in the
  111. If the lymphocyte is a B cell in an antigen challenge
    • the antigen provokes a humoral response
    • antibodies are produced
  112. What is the first step of clonal selection?
    B cell is activated when antigens bind to its surface receptors and cross-link them
  113. What is the second step of clonal selection?
    Receptor-mediated endocytosis of cross-linked antigen-receptor complexes occurs
  114. What is the third step of clonal selection?
    Stimulated B cell gros to form a clone of identical cells bearing the same antigen-specific receptors (T cells are usually required to help B cells achieve full activation)
  115. Most clone cells become ______________ and secrete specific ____________________ at the rate of ____________________
    • plasma cells
    • antibodies
    • 2000 molecules per second for four to five days
  116. What is the fate of the clones that become secreted antibodies?
    • Circulate in blood or lymph
    • Bind to free antigens
    • Mark the antigens for destruction
  117. Clone cells that do not become plasma cells become _______________ and provide _________________ and mount an ___________________
    • memory cells
    • immunological memory
    • immediate response to future exposures of the same antigen
  118. Primary immune response occurs on ______________, has a lag period of _____________________, peak levels of plasma antibody are reaches in ____________ antibody levels then _________
    • the first exposure to a specific antigen
    • 3 to 6 days
    • 10 days
    • decline
  119. Secondary immune response occurs on ____________, sensitized memory cells ______________, antibody levels peak in _____________, antibodies bind with ____________, antibody level can _______
    • re-exposure to the same antigen
    • respond within hours
    • 2 to 3 days at much higher levels
    • greater affinity
    • remain high for weeks to months
  120. Active humoral immunity occurs when
    B cells encounter anitgens and produce specific antibodies against them
  121. What are the two types of active humoral immunity?
    • Naturally aquired-response to a bacterial or viral infection
    • Artificially required-repsonse to a vaccine of dead or attenuated pathogens
  122. Vaccines spare _____________________ and provide __________________
    • us the symptoms of the primary response
    • antigenic determinants that are immunogenic and reactive
  123. In passive humoral immunity B cells are not ________________ and _________________ does not occur
    • challenged by antigens
    • immunological memory
  124. What are the two types of passive humoral immunity?
    • Naturally aquired-antibodies delivered to a fetus via the placenta or to infact through milk
    • Artificially aquired-injection of serum, such as gamma globulin (protection is immediate but ends when antibodies naturally degrade in the body)
  125. Antibodies are (3)
    • immunoglobulins-gamma globulin portion of blood
    • proteins secreted by plasma cells
    • capable of binding specifically with antigen detected by B cells
  126. What is the basic structure of an antibody?
    • T or Y shaped monomer of four looping linked polypeptide chains
    • Two identical heavy (H) chains and two identical light (L) chains
    • Variable (V) regions of each arm combone to form two identical antigen-binding sites
  127. The constant region of antibody stem determines _______________, ________________ and how
    • the antibody class
    • the cells and chemical that the antibody can bind to
    • the antibody class functions in antigen elimination
  128. What are the 5 antibody classes?
    lgM, lgA, lgD, lgG and lg E
  129. A pentamer; first antibody released
    Potent agglutinating agent
    Readily fixes and activates complement describes
  130. Monomer or dimer; in mucus and other secretions
    Helps prevent entry of pathogens describes
  131. Monomer attached to the surface of B cells
    Functions as a B cell receptor describes
  132. Monomer attached to the surface of B cells
    Functions as a B cell receptor describes
  133. Monomer, 75-85% of antibodies in plasma
    From secondary and late primary responses
    Crosses the placental barrier describes
  134. Monomer active in some allergies and parasitic infections
    Causes mast cells and basophils to release histamine describes
  135. Billions of antibodies result from
    somatic recombination of gene segment
  136. Hypervariable regions of some genes increase antobody variations through
    somatic mutations
  137. Each plasma cell can switch the type of
    H chain produced, making an antibody of a different class
  138. Antibodies inactivate and _________________ and form ___________________
    • tag antigens
    • antigen-antibody (immune) complexes
  139. What are the defense mechanisms used by antibodies?
    • Neutralization and agglutination (the two most important)
    • Precipitation and complement fixation
  140. Describe naturalization by antibodies
    • Simplest mechanism
    • Antibodies block specific sites on viruses or bacterial exotoxins
    • Prevent these antigens from binding to receptors on tissue cells
    • Antigen-antibody complexes undergo phagocytosis
  141. Describe agglutination by antibodies
    • Antibodies bind the same determinants on more than one cell bound antigen
    • Cross-linked antigen-antibody complexes agglutinate
    • Ex. clumping of mimatched blood cells
  142. Describe precipitation
    • Soluble molecules are cross linked
    • Complexes precipitate and are subject to phagocytosis
  143. What is the main antibody defense against cellular antigens?
    Complement fization and activation
  144. Several antibodies bind close together on a cellular antigen, their complement-binding sites trigger complement fixation into the cell's surface describes _________________-- and then __________________
    • Complement fization and activation
    • complemet triggers cell lysis
  145. Activated complement functions
    • Amplifies the inflammatory response
    • Opsonization
    • Enlists more and more defensive elements
  146. What is opsonization?
    coating the pahtogen in complement and anitbodies
  147. Monoclonal antibodies are _________________ and are produced by ___________________. They proliferate ____________and have the ability to ______________________. Are used in _____________________
    • commercially prepared pure antibody
    • hybridomas (cell hybirds: fusion of a tumor cell and a B cell
    • indefinitly
    • produce a single type of antibody
    • research, clinical testing, and cancer treatment
  148. T cells provide defense against
    intracellular antigens
  149. What are the two types of T cell receptors?
    • T cell antigen receptors
    • Cell differentiation glycoproteins
    • CD4 or CD8 Play a role in T cell interactions with other cells
  150. CD4 cells become
    Helper T cells (TH) when activated 4+2=Helper
  151. CD8 cells become
    cytotoxic T cells (TC) that destroy cells harboring foreign antigens 8+1=cytotoxic
  152. What are the two other types of T cells?
    • Regulatory T cells (TREG)
    • Memory T cells
  153. Antibodies of the humoral response are
    the simplest ammunition of the immune system
  154. Targets of the humoral response are
    bacteria and molecules in extracellular environment (body secretions, tissue fluid, blood and lymph)
  155. T cells of the cell mediated response
    recognize and respond only to processed fragments of antigen displayed on the surface of body cells
  156. The targets of the cell mediated response are
    • body cells infected by viruses or bacteria
    • abnormal or cancerous cells
    • cells of infued or transplanted foreign tissue
  157. What are the two types of MHC proteins that are important to T cell activation?.
    • Class 1 MHC proteins-displayed by all cells except RBCs
    • Class II MHC proteins-displayed by APCs (dendritic cells, macrophages and B cells)
    • Both types are synthized at the ER and bind to peptide fragments
  158. Immunocompetent T cells are activated when
    their surface receptors bind to a recognized antigen (nonself)
  159. T cells must simultaneously recognize
    • nonself (the antigen)
    • self (an MHC protein of a body cell)
  160. Class I MHC proteins bind with
    fragment of a protein synthesized in the cell (endogenous antigen)
  161. Endogenous antigen is a ___________________ in a normal cell; a _____________ is an infected or abnormal cell
    • self-antigen
    • nonself antigen
  162. Class I MHC proteins inform _______________ of the presence of microorganisms hiding in cells
    • cytotoxic T cells
    • (cytotoxic T cells ignore displayed self-antigens)
  163. Class II MHC proteins bind with
    fragment of exogenous antigens that have engulfed and borken in a phagolysosome
  164. Class II MHC proteins are recognized by
    helper T cells
  165. APCs (most often a ____________) migrate to lymph nodes and other lymphoid tissues to
    • dendritic cell
    • present their antigens to T cells
  166. What are the two steps of T cell activation?
    • Antigen binding
    • Co-stimulation
  167. What is MHC restriction?
    CD4 and CD8 cells bind to different classes of MHC proteins
  168. CD4 cells bind to
    antigen linked to class II MHC proteins of APCs
  169. CD8 cells are activated by
    antigen fragments linked to class I MHC of APCs
  170. Dendritic cells are able to obtain other cells' endogenous antigens by
    • engulfing dying virus-infected or tumor cells
    • importing antigens through temporary gap junctions with infected cells
  171. Co-stimulation requires
    T cell binding to other surface receptors of an APC
  172. Dendritic cells and macrophages produce
    surface B7 proteins when innate defenses are mobilized
  173. Cytokines (interleukin 1 and 2 from APCs or T cells) trigger
    proliferation and differentiation of activated T cell
  174. Without co-stimulation, ___________ occurs and
    • Anergy
    • T cells become tollerant to that antigen
    • are unable to divide
    • do not secrete cytokines
  175. T cells that are activated enlarge, _____________ and form _____________. They also _________ and perform functions according to their _______________
    • proliferate
    • clones
    • differentiate
    • T cell class
  176. Once primed by APC presentation of antigen, helpter T cells (TH)
    • help activate T and B cells
    • Induce T and B cell proliferation
    • Activate macrophages and recruit other immune cells
  177. Helper T cells interact directly with ________
    B cells diplaying antigen fragments bound to MHC II receptors
  178. helper T cells stimulate ____________ to divide more rapidly and begin ____________
    • B cells
    • antibody formation
  179. B cells may be activated without TH cells by
    binding to T cell-independant antigens
  180. Most antigens require _________________ co-stimulation to activate B cells
  181. ________________ cause dendritic cells to express co-stimulatory molecules required for CD8 cell activation
    Helper T cells
  182. Cytotoxic T cells (TC) directly
    Where are they found?
    • attack and kill other cells
    • Blood, lymph and lymphoid organs
  183. Targets of cytotoxic T cells are
    • virus-infected cells
    • cells with intracellular bacteria or parasites
    • cancer cells
    • foreign cells (transfusions and transplants)
  184. Cytotoxic T cells bind to ____________ and can destroy _____________-
    • a self-nonself complex
    • all infected or abnormal cells
  185. Describe mechanisms cytotoxic cells use to kill
    • Tc cells releases perforins and granzymes by exoctytosis
    • Perforins create pores through which granzymes enter the target cell
    • Granzymes stimulate apoptosis
  186. What are the abnormal signs recognized by NK cells
    • Lack of class I MHC
    • antibody coating a target cell
    • different surface marker on stressed cells
  187. NK cells use the same mechanisms as __________ for killing their targets
    Tc cells
  188. Regulatory T cells (TReg) dampen the immune response by
    direct contact or by inhibiting cytokines
  189. TReg is important in
    preventing autoimmune reactions
  190. Multiple sclerosis, myasthenia gravis, Grave's disease, type I diabetes mellitus, systemic lupus erythematosus (SLE), glomerulonephritis, and rheumatoid arthritis are examples of
    Autoimmune diseases
  191. What is the first mechanism of an autoimmune disease?
    Foreign antigens may resemble self-antigens
  192. What is the second mechanism of an autoimmune disease?
    New self-antigens may appear, generated by gene mutations and changes in self-antigens by hapten attachment or as a result of infectious damage
  193. What is the third mechanism of an autoimmune disease?
    Release of novel self-antigens by trauma of a barrier (ex. the blood brain barrier)