MCAT Immune and digestive system

  1. bone marrow produes leukocytes (WB)
  2. spleen function in immune system
    location of blood storage and activation of B-cells (plasma cells)
  3. function of plasma cells
    b-cells that produce antibodies as part of adaptive immunity
  4. when B-cells leave spleen they are mature but naive as well because they have yet to encounter an antigen
  5. thymus causes t-cells to mature there
  6. lymph nodes function
    a place for cells to communicate and mount attack also where B-cells get activated
  7. areas in which there can be a potential invasion by pathogens
    gut associated lymphoid tissue
  8. 4 location of the immune system and their functions
    • lymph nodes - filter lymph and site where immune responses can be mounted
    • BM - site of immune cell production
    • T-is the site of tcell maturation
    • Spleen - storage area for blood and lymph and site of mounting immune responses
  9. 2 leukocytes and their functions
    • granualcytes - granules released by exocytosis and are effective against bact,fungi,patho
    • agranualcytes - absence of granuels
  10. hematopoetic stem cell breaks off into
    • lymphoid SC
    • myeloid SC
  11. the lymphoid stem cell makes these 3 cells
    • NK
    • T cell (helper T and cytotoxic)
    • B cell (plasma)
  12. the myeloid stem cell makes 6 progenitor
    • granulocyte (dendritic neutrophil) monocyte (macrophage)
    • eosinophil
    • basophil (mast cell)
    • megakaryocyte (platelets)
    • erythroid (erythrocytes)
  13. how is skin the nonspecific first line of defense
    • antibacterial enzymes (defensins) are found on skin
    • sweat has antimicrobial properties
  14. skin and GI tract are not non specific immune response
  15. compliment
    number of pro that act on non specific defense against bacteria
  16. how can compliment be activated (2) and how they work
    • classical pathway - binding of AB to patho
    • alternative pathway - no need for antibodies
  17. function of interferons 3
    • proteins that prevent viral replication and dispersion of viral and cellular proteins from nearby cells that are produced by cells that have been infected with the virus
    • decrease permeability of these cells so the virus cant infect as well
    • unregulate MHC class 1/2 to increase antigen presentation and better detection of infected cells
  18. activation of macrophages - 3
    • phago invaders through endocytosis
    • digest invader
    • presents pieces of invader to other cells using MHC which binds to a patho pep and carries it to cell surface
  19. cytokines
    chemical substances that stim inflammation and recruit additional immune cells to area
  20. all nucleated cells display MHC 1 because the cell needs to be able to produce the protein and present it on the surface
    **helps to monitor health of cells, if they are invaded by a virus then they will present an unfamiliar protein on their surface
  21. endogenous pathway
    • MHC 1 pathway that binds antigens from inside of the cells
    • certain intracellular pathogen can be killed by Cytotoxic to prevent infection of other cells
  22. MCH class 2 function
    molecules (macro) that display professional antigens that they pick up from phago cells from the environment
  23. exogenous pathway
    • antigens are presented outside of the cell
    • can activate adaptive and innate system
  24. pattern recognition receptors
    • toll like receptors
    • recognize the category of the invader and allows specific cytokines to recruit the right type of immune cells
  25. natural killer cells
    nonspecific lymphocyte, detect down regulation of MHC and induce apop
  26. neutrophils 5 characters
    • most common leukocyte in blood
    • phago,macro,target bact
    • follow the bact using chemotaxis
    • can detect when a bact has been opsonized (marked with AB from b-cell)
  27. chemotaxis
    the sensing of certain products given off by bact and migrate neutro to the cells
  28. opsonized
    the marking of bacteria wih AB from B-cell
  29. dead neutro=pus
  30. eosinophils 2
    • involved in allergic reactions
    • release a large amount of histamine
  31. eosinophil release histamine that does
    vasodilation and increase blood vessel leakiness allowing immune cells to be released to move out of blood stream and into tissue
  32. basophils/mast
    • least amount
    • involved in allergic reactions
  33. dendritic cells
    • presents antigens from patho
    • attack those that present displayed antigens
  34. 3 possible affects of AB secreting in body fluids
    • bind to specific antigen, ab might attract other leuko to phago antigen (opsonization)
    • AB can cause agglutinate to be phago
    • AB can block ability of patho to invade tissue to neutralize it
  35. when AB binds to antigen, responses will be (or)
    • secreted into body fluids
    • binding of antigen to b cell casing activation of the cell
    • AB are bound to antiens on surface of the mast cell, degranulation occurs causing histamine and an inflammatory rxn
  36. agglutinate
    forms large insoluble complexes to be phago
  37. 20892-004-4E71BC2F
    • 2 heavy and 2 light chains
    • disulfide linkages hold them together
    • antibinding region (look or antibind site) at the end of the variable domain
    • constant region (domain) is where NKC,maco,mono,eosino have receptors for and can activate a compliment cascade

    • why does it take so long to initiate a AB response 2
    • specific poplypep sequences will bind to one specific antigen sequence
    • b-cell undergoes hypermutation  to find the best match antigen to bind to with high affinity (clonal selection)

    • 5 antibody isotopes
    • IgM,D,E,G,A

    • isotope switching
    • cell can change which isotype of the AB they produce when stim by specific cytokines
  38. plasma cells make the antibodies
    mem b cells wait for a response that has occurred before so they can act on it
  39. primary response - activation of B cells
    secondary response - the immune response for the pathogen
  40. germinal enters
    sites where b-cells proliferate and mature in the lymph nodes
  41. lactels
    • lymphatic vessels at the center of villus in the small intestine
    • receives fats packaged into chylomicrons by intestinal mucosal cells for support
  42. chyle
    lymphatic fluid carrying many chylomicrons that has a white fluid appearance
  43. edema
    swelling due to fluid collecting in tissue where oncotic blood pressure decreases and less water is driven back into tissue
  44. lymphatic system structure
    one way vessels that become larger as they move to the center of the body, they carry lymphatic fluid and join to comprise a large thoracic duct in posterior chest that delivers fluid into the left subclavian vein (near heart)
  45. function of lymphatic system structure
    • fluid leaves the bloodstream and goes into tissues at the capillaries. Hydrostatic and oncotic pressure helps to determine the amount of fluid that leaves the tissue.
    • oncotic pressure of blood draws water back into vessel at end of venuel when hydrostatic pressure decreases
    • venuel end has less net pressure pushing fluid out, so small amount of fluid remains in the tissue
  46. positive selection of T-cells
    • maturing only cells that can respond to the presentation of antigen on MHC
    • **don't respond to mhc undergo apop because it can not recog the periphery**
  47. negative selection of T-cells
    causing apop in cells that are self reactive (activated
  48. 3 major types of t cells
    • helper (CD4+)/cytotoxic (CD8+)
    • suppressor/regulatory cells
    • memory
  49. helper CD4+ cells function
    release lymphokines that help to recruit other immune cells such as macro,cyto,plasma
  50. HIV prevents the immune system from mounting an immune response
  51. cytotoxic T-cells (CD8+)
    directly kill virally infected cells by injecting toxic chems that promote apop into effected cells
  52. suppressor/regulatory T-cells
    • express CD4+ and foxp3
    • tone down the IR once infection has been contained and then turn off self reactive lymphocytes to prevent autoimmune diseases (self tolerance)
  53. how the body reacts to a bacterial infection after lesion 6
    • macro engulf bac and release inflame mediators
    • cells digest and present antigens of pathogen on surface for MHC II
    • cytokines released attract neutro/macro/inflam cells (neutro) resulting in releasing histamine and leaky capillaries
    • dendritic cells go to nearest lymph node to present antigen to B-cell to create plasma and mem cells
    • the AB goes into the blood stream to go to infected area while the nearest lymph node activates T-cells (CD4). CD4+ comes in 2 types, Th1 and Th2. Th1 cells release interferon gamma which activates macro and increase ability to kill bact. Th2 cells help to activate B-cells
    • pathogen has been eliminated, plasma cells die, but mem T and B cells remain
  54. how the body reacts to a viral infection
    • infected cell produce interferons that reduce the ability of the other cells to become infected. The infected cell also produces intracellular proteins on their surface with MHC 1
    • CD8 recognize MHC1 with antigen complex as being foreign and will inject toxins in cell to promote apop
    • MHC is not common on the cell once the virus has infected it so NKC will recognize its absence and will help cause apop
  55. self antigens
    pro and carbo on surface of every cell in body that helps to signal to immune cells that the cell is not threatening and should not be attack
  56. autoimmunity
    when the immune system fails at detecting between self and foreign cells so they attack the good cells
  57. hypersensitivity reactions
    immune system are hypersensitive to antigens and become overactivated when antigens are encountered
  58. autoimmune diseases can be treated with various therapies
    ex:glucocorticoids that have immunosuppressive qualities
  59. active immunity
    immune system that is stim by natural or artificial paho to produce AB against it specifically
  60. passive immunity
    results from the transfer of AB to an individual only
  61. intracellular digestion
    oxidation of glucose and fatty acids for energy (metabolism)
  62. extracellular digestion
    nutrients are obtains from food occurs within the lumen of alimentary canal
  63. alimentary canal consists of these
    mouth t anus sectioned off by sphincters or circular smooth muscles that can contract to allow compartmentalization of function
  64. digestion 2 processes
    • mechanical
    • chemical
  65. mechanical digestion
    physical breakdown of food particles
  66. chemical digestion
    enzymatic cleavage of chem bonds into particles that can be absorbed starch,carbo,lipids (transportation of products of digestion from the digestive tracts into circulatory system to distribute to tissues and cells)
  67. process of the digestive tract
    mouth>pharynx>esophagus>stomach>small intestine>large intestine>rectum
  68. the salivary glands, pancreas, liver and gallbladder
    provide enzymes and lubrication needed to aid in the digestion of food
  69. enteric nervous system
    collection of 10^6 neurons that governs the function of the gastrointestinal sysem. Trigger peristals/rhythmic contractions of the gut to move materials through the system
  70. we get tired after a big meal because parasympathetic activity of digesting and secretions from exocrine glands and the promotion of peristalsis
    all glands of the body are innervated by ParaNS except sweat
  71. salivary amylase function
    hydrolyzing starch into smaller sugars
  72. lipase
    catalyzes the hydrolysis of lipids
  73. larynx (respiratory tract)
    • nasopharynx (behind nasal cavity)
    • oropharynx (back of the mouth)
    • laryngopharynx (above vocal cords)
  74. the esophagus (top) is under somatic (voluntary) control while the rest of GI tract is under automatic
  75. function of oropharynx
    (upper esophageal sphincter) is where swallowing is initiated, as peristalsis occur, the bolus goes down the stomach toward the lower esophageal sphincter (cardiac sphincter) where it relaxes and opens to allow the passage of food
  76. 4 main divisions of the stomach
    • fundus
    • body
    • antrum
    • pylorus
  77. fundus and body contain mostly gastric glands while antrum and pylorus contain pyloric glands
  78. mucosa of the stomach contains gatric and pyloric glands
  79. gastric glands
    responds to signals from vagus nerve of paraNS which are activated by the brains response to sight,taste,and smells
  80. 3 cell types of gastric glands
    • mucous
    • chief
    • parietal
Card Set
MCAT Immune and digestive system
mcat immune and digestive system flash cards