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immunity

hanna akhrass biology - Englisch 110 Karten

Karten in diesem Stapel (110)

  1. 1what are pathogens?microorganisms which cause infectious diseases, such as; bacteria, fungi, viruses
  2. 2what is a disease?physical/mental symptoms caused by a pathogen
  3. 3what requirements do microorganism need to have to be classed as a pathogen?-gain entry to the host
    -colonise the tissue of the host
    -resist the defense of the host
    -cause damage to hosts tissues
  4. 4what happens if a pathogen gets into the host and colonises its tissue?causes an infection
  5. 5how can an infection lead to a disease?when an infection leads to recognise symptoms in the host
  6. 6what is transmission?when a pathogen is transferred from one individual to another
  7. 7humans three lines of defence?-non specific barriers
    -non specific immune system
    -specific immune system
  8. 8what is a non specific barrier?the skin and associated chemicals to stop microbes entering the body
  9. 9what is a non specific immune system?the phagocytes that quickly destroy microbes that pass the first line of defence
  10. 10what is a specific immune system?the lymphocytes that kill any microbes that pass the second defence and remain on guard for future attacks
  11. 11how does the skin prevent microbes entering the body?-has a tough, impenetrable barrier (epidermis)
    -thick
    -epidermis cells toughened with keratin
  12. 12how does saliva/tears/sweat prevent microbes entering the body?-contain lysozyme enzymes
    -these enzymes destroy bacteria growing on skin surface by digesting their peptidoglycan cell walls
  13. 13how does the respiratory tract prevent microbes entering the body?-protected by sticky mucus secreted by goblet cells
    -goblet cells trap pathogens and other particles in inhaled air before they can reach the delicate alveoli
    -mucus contains lysozymes
    -cilia constantly sweep the mucus upwards to the throat where it is swallowed so the pathogens are killed by stomach acid
  14. 14how does the digestive tract prevent microbes entering the body?-protected by a concentrated acid in stomach
    -acid denatures pathogenic enzymes
  15. 152 ways microbes enter the body?-gas exchange system
    -digestive system (food/water via mouth)
  16. 16how does mucus prevent microbes entering the body?covers exchange surfaces and forms a thick sticky barrier that is difficult to penetrate
  17. 17how do pathogens cause diseases?-by damaging hosts tissue
    -producing toxins
  18. 18how do the pathogens damaging the hosts tissue causes diseases?-prevents tissues functioning properly
    -inhibit synthesis of DNA, RNA and proteins by the hosts cells
    -break down membrane of hosts cells
  19. 19what is friendly bacteria?-bacteria that colonise the skin, mouth, lower digestive tract, respiratory tract and vagina
    -prevent infections by out competing pathogens for food and space
  20. 20where are leukocytes derived from?stem cells, produced in the bone marrow
  21. 21what happens to the stem cells in bone marrow?-they differentiate into different kinds of leukocytes
  22. 22different types of leukocytes?-phagocytes
    -granulocytes
    -T lymphocytes
    -B lymphocytes
  23. 23what are phagocytes for?for phagocytosis
  24. 24what is granulocytes for?inflammation
  25. 25what are T lymphocytes for?cell-mediated immunity
  26. 26what are B lymphocytes for?antibody mediated immunity
  27. 27what happens after WBC (white blood cells) are produced?-transported to different parts of the body via the blood
    -final destination is the lymphatic system
  28. 28what is the lymphatic system made up of?a series of 2 blind-ending tubes called 'lymph ducts' or 'lymph vessels', which drain tissue fluid back into blood stream
  29. 29where are pathogens found in the body specifically?-tissue fluid
  30. 30where do WBC carry out pathogen destruction?-lymphatic system
    -WBC collect and destroy pathogens at lymph nodes and spleen
    -tissue fluid (containing pathogens) is drained
  31. 31What is the second line of defence?(non-specific immune system)
    -phagocytes
    -granulocytes
  32. 32structure of phagocytes?-large
    -irregularly shaped
  33. 33what do phagocytes do?-remove cell debris/dust particles
    -remove pathogens
  34. 34how do phagocytes remove debris/pathogens from the body?-surround and ingest pathogen by phagocytosis to form a vesicle
    -vesicle fuses with lysosomes (contain hydrolytic enzymes)
    -these enzymes are released into the phagosome
    -then digests the microbe
  35. 35where are granlocytes found?connective tissue throughout the body
  36. 36what is inflammation?when granulocytes cause a localised response to an injury or infection
  37. 37what chemical do granulocytes release?a chemical e.g. histamine
  38. 38what does the chemical released by granulocytes do?stimulates;
    -vasodilation (increase blood flow to the area-turns area red)
    -capillary leakage (so phagocytes can enter local tissue fluid-area swells)
    -blood clotting (seal wound-scab forms)
  39. 39what is in puss?dead pathogens and phagocytes in excess tissue fluid
  40. 40What is a fever?-histamine and bacterial toxins cause an increase in the body's temperature from 37 C up to 39 C
    -helps immune system
    -inhibits growth of some bacteria
  41. 41what is the third line of defence?specific immune system
  42. 42what forms the specific immune system? And what is it's role?-lymphocytes form the specific immune system
    -kills invading pathogens
    -remembers pathogens features so that future infections can be prevented
    -recognises specific foreign cells by antigens
  43. 43what type of animals is the only type to have a specific immune system?vertebrates
  44. 44What are antigens?-large protein molecule on outer surface of a cell
    -cells from different individuals have different antigens, all cells from one individual have same antigens
    -genetically controlled (close relatives have more similar antigens)
  45. 45what are 'self'antigens which the immune system recognises as its own
  46. 46what are 'non-self'?antigens the immune system recognises as foreign
  47. 47what are antibodies?-protein molecule that binds specifically to an antigen
  48. 48structure of antibodies?-4 polypeptide chains (2 heavy 2 light)
    -joined by strong disulphide bonds
    -Y shape structure
    -stem=constant region
    -ends of arms=variable regions
  49. 49what is the stem of the antibody?-constant region
    -same amino acid sequence/structure in all antibodies
  50. 50ends of the arms of antibody?-variable regions
    -different antibody molecules have different amino acid sequence/structures
    -where antigens bind to form a highly specific antigen-antibody complex
  51. 51What do B lymphocytes do? what are they triggered by?-make antibodies
    -cause antibody-mediated response
    -triggered by non-self antigens on surface of pathogens/toxins they produce
  52. 52what do B Lymphocytes become?-become either plasma cells/
    -secreting antibodies/
    -memory cells for future invasions by same pathogens
  53. 53where are B and T cells made and where do they mature?-both cells made in bone marrow
    -B= matures in bone marrow
    -T= matures in thymus gland
  54. 54where are antibodies attached to the B cell?by the outside of their cell membrane-behave like receptors
  55. 55What happens when an antigen binds to their receptors?-an antigen-antibody complex forms
    -B cell clones its self
    -millions of specific antibodies secreted into body
  56. 56role of T cells?-kill infected cells
    -help other parts of immune response to work more efficiently
    -triggered by infected/cancerous cells
    -cause cell-mediated response
    -form antigen-receptor complexes
  57. 57what do T cells become after triggered by cancerous/infected body cells?T killer cells/T helper cells/T memory cells
  58. 58T cells receptors compared to B cell receptors?-similar
    -do not secrete antibodies
  59. 59how do T cells recognise infected cells?-infected cells place pathogens antigens on their surface (forms antigen-presenting cells)
    -process is self destructing but also prevents virus inside it from 'lysing' the cell and releasing hundreds of viruses
  60. 60what happens as soon as a match is found between a B or T cells and its matching receptor molecule?-the binding of the antigen to the receptor stimulates the lymphocyte to divide repeatedly by mitosis
    -creates army of identical clones B or T cells
  61. 61what is clonal selection?the army of identical clones B or T cells created by the lymphocyte dividing (selection of cloning)
  62. 62cell mediated immunity (cytotoxic/killer T cells)?-killer T cells bind to antigens on surface of infected cells
    -they kill cells by releasing proteins which insert into the cell membrane of the other cell
    -creates pore which causes the cell to burst
  63. 63cell mediated immunity (helper T cells)?-bind to antigens presented on infected cells
    -secrete chemicals called cytokines
    -this stimulates all the other white blood cells and speeds up immune responses
  64. 64what does AIDS/HIV do to helper T cells?-destroys t helper cells
    -so immune system doesn't work nearly as well without them
  65. 65cell mediated immunity (memory T cells)?-remain in blood for decades after infection
    -so same antigen will be identified quickly in a subsequent infection
    -and T cells will quickly divide to form killer T cells and helper T cells
  66. 66antibody-mediated immunity (plasma cells)?-secrete soluble antibodies that are carried around the blood, lymph and tissue fluid
    -soluble antibodies bind to any antigens they come into contact with=antibody-antigen complexes
  67. 67why is it highly likely that every antigen will be targeted by an antigen?because a huge amount of antibodies are produced in the body
    -high amount of rough ER for synthesising and transporting antibodies out the cells
  68. 68Various ways antibodies help kill cells?-by binding to antigens on pathogens
    -binding to free toxin proteins
    -linking antigens together into large clumps
  69. 69how do antibodies binding to antigens on pathogens help kill cells?prevents them from attaching to and infecting cells
  70. 70how do antibodies binding to free toxin proteins help kill cells?prevents them causing a disease
  71. 71how do antibodies help kill cells by linking antigens together into large clumps?-each antibody molecule has two antigen binding sites (one on each arm of the Y)-This allows antibodies to stick antigens together= "agglutination"
    -allows pathogens or infected cells to be easily destroyed by phagocytes or killer T cells
  72. 72cell mediated immunity (memory B-cells)?-continue to secrete antibodies in small quantities for decades
    -can multiply rapidly to produce an instant supply of plasma cells if the same pathogen invades again
  73. 73primary immune response ?-the slow and weak response to a new infection
    -during this period the symptoms are shown due to; toxins and cell death due to the pathogen + immune response itself
  74. 74what is phagocytosis?when large particles are too big to cross membrane so need to be engulfed by phagocytes in the form of vesicles formed from the cell surface membrane
  75. 75why does it take several days for clonal selection to take place when a new antigen is encountered?-there's only a few lymphocyte cells of each kind for the antigen to encounter
    -clone army tends to be small
  76. 76What is the secondary immune response?-memory cells (T&B) remain in blood
    -so after an infection by the same antigen, the clonal selection stage occurs much faster and greater number of antibodies are produced
    -pathogen is destroyed before it reproduces enough to cause a disease
  77. 77why does the secondary immune response not work with the common cold and flu?-the pathogens have constantly changing antigens (antigenic variability)
    -causes a new primary response, with all the symptoms of the accompanying disease
  78. 78what is antigenic variability ?when the pathogens antigens are constantly changing
  79. 79what is active immunity?becoming immune through acquiring a disease
  80. 80what is artificial immunity?-injecting people with an antigen that will promote the primary immune response
    -but modified so that it's non-virulent (won't cause the disease)
    -immune system makes memory cells so if a person is infected with the real virulent pathogen, the more effective secondary immune response is triggered and the pathogen is killed before it causes the disease
  81. 81what do vaccinations provide to a number of potentially fatal diseases?artificial immunity
  82. 82what do people normally get vaccinated against?diphtheria, tetanus, whooping cough, polio, measles ,mumps, rubella, and TB
  83. 83what ad why is a booster given?causes the body to make more memory cells
  84. 84what is passive immunity?-produced by introduction of antibodies into individuals from an outside source
    -antibodies not produced by individual and are not replaced when they're broken down by the body, so the immunity is short-lived
  85. 85what is passive immunity used for?-rabies
    -tetanus
    -measles
    -hepatitis B
  86. 86example of passive immunity occurring naturally?-when mother passes antibodies to her child
    -across placenta to fetus
    -passed through milk
    -babies digestive system doesn't function at this stage the antibody proteins can be absorbed intact
    -helps baby survive in world full of pathogens
  87. 87why isn't passive immunity long lasting?person doesn't have memory cells so the antibodies eventually will be digested and the person can't make more
  88. 88what are monoclonal antibodies?isolating a single type of antibody and cloning it
  89. 89how monoclonal antibodies are made?1)inject mouse with the antigen that you need antibodies for
    2)after few days mouse is killed and B cells extracted from spleen
    3)B cells grown in culture flask, where they multiply by mitosis, making millions of identical cloned cells each secreting identical antibodies (monoclonal antibodies)
  90. 90two problems with extracting B cells from mouse's spleen?-B cells won't grow in test tubes
    -the spleen extract contains a mixture of thousands of different B cells each with specific antibodies
  91. 91How to solve the problem of B cells not being able to be grown in test tubes?-using immortal cancerous mouse cells (divide indefinitely in vitro)
    -mixed within myeloma cells that divide readily outside the body (tumour) in a petri dish and fused with a detergent
    -fused cells= hybridoma cells (have properties of both cell types being able to grow in vitro and produce antibodies)
  92. 92How to solve the problem of the spleen extract containing a mixture of many B cells each making their own specific antibodies?-diluting cells into hundreds of wells in an immunoassay plate (one cell per well)
    -cells multiply in wells and secrete a different clone of antibodies in each well
    -each well is screened for production of the required antibody
  93. 93How are the fused cells (in production of monoclonal antibodies) separated?-under microscope
    -each cell is cultured to form a group
    -each group is tested to see whether it id producing the required antibody
  94. 94uses of monoclonal antibodies?-can be made to an antibodies can be made to an antigen found on a specific cancer cell
    -detects presence of hCG in urine in a pregnancy test strip
    -in passive immunity to help the body's normal immune response to a serious infectioj
  95. 95How can monoclonal antibodies be used to target cancer cells?-antibodies can be made to an antigen found on specific cancer cell
    -a toxic agent is bound to the antibody
    -antibody toxin complex is injected into a cancer patient + the antibody will ensure the agent is carried only to cancer cells and nowhere else
  96. 96how are monoclonal antibodies used in pregnancy tests?antibodies of the hormone hCG, produced in pregnancy are bound to a test strip to detect the presence of hCG in urine
  97. 97stage 1 of HIV?-Acute
    -3-12 weeks
    -flu like symptoms
    -HIV antibodies found in blood
    -loss of T helper cells
    -infected T helpers are killed by T killers (reduces rate of virus replication but doesn't stop it)
  98. 98Stage 2 of HIV?-Chronic stage
    -symptoms disappear
    -T killer cells kill off infected CD4 T helper cells
    -lasts many years in healthy people
    -susceptibility to diseases increase gradually
    -reactivation of dormant diseases like shingles and TB
  99. 99stage 3 of HIV?-disease stage
    -viral load becomes so great
    -T helper level falls to below half a normal level
  100. 100Stage 4 of HIV?-advanced
    -low, badly damaged immune system
    -opportunistic infections-TB, meningitis, pneumonia
    -When the number of your CD4 cells falls below 200 cells/mm3= AIDS
    -if you develop one or more opportunistic infections=AIDS
  101. 101What is HIV?-human immuno deficiency virus
    -weekends immune system
    -retro virus
    -caused by humans eating orangutans
    -leads to AIDS (acquired immuno deficiency virus)
    -attacks T cells/cD4 cells and uses them to make copies of itself
  102. 102how is HIV transmitted?-sexual contact
    -enters blood stream via mucous membranes lining the vagina, rectum and mouth
    -Macrophages and dendritic cells on the surface of mucous membranes bind virus and shuttle it into the lymph nodes
    -which contain high concentrations of helper T cells (CD4+ T cells)
  103. 103What happens after HIV binds to cell membrane/T helper cell receptors?-virus' genetic material inserted into cell
    -reverse transcription inserts DNA into human genome
    -cell produces HIV
    -immune system initiates anti-HIV antibody and cytotoxic T cell production (can take 1-6 months)
  104. 104What does the loss of T helper cells mean?-macrophages won't be activated
    -B cells won't be activated
    -T killer cells won't be activated
  105. 105How does HIV make copies of itself?-HIV attaches to CD4/T helper cell by the glycoproteins on surface of HIV
    -releases contents into CD4/T helper
    -Once inside the cell, HIV changes its genetic material (HIV RNA) into HIV DNA via the enzyme reverse transcriptase
  106. 106reverse transcription of HIV?-HIV DNA then makes long strands of mRNA proteins, and transports them towards the edge of the cell
    -This is then used for producing more HIV
  107. 107what gases do we exchange?-oxygen
    -carbon dioxide
    -water
    -glucose
  108. 108what is agglutination?-sticks pathogens together
    -prevents pathogens working
    -makes it easier for it to engulf
  109. 109what is antigen presentation-warns body a pathogen is present
    -white blood cell infects itself with pathogen to warn body
  110. 110—

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- biology Karteikarten am immunity, erstellt von hanna akhrass am 22/01/2016.
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