The immune system Honors Anatomy & Physiology - PowerPoint Presentation

1. TheimmunesystemHonors Anatomy & PhysiologyChapter 21

2. 2 Defense Systems

3. Innate Immunitynonspecific defense that is active immediately upon infectionfound in all animals & plantsincludes:outer coveringskin or shellchemical secretions@ openings to interior of body

4. Mechanical Barriers:skin & mucosaeskin, mucous membranes & their secretions highly effective barriers…unless not intactepidermis with thick keratinized layers of cells blocks most microorganismskeratin resistant to most bacterial enzymes & toxinsintact mucosae just as protective

5. Protective chemicals1. Acidacidic pH inhibits bacterial growth (bacteriostatic)2. EnzymesLysozyme in saliva, tears, sputum bacteriocidalgastric enzymes also bacteriocidal3. Mucin + water  sticky lining of digestive & respiratory passages: traps pathogens4. Defensins: broad-spectrum antimicrobial peptides secreted by mucous membranes & skin5. Other: lipids in sebum & dermicidin in eccrine sweat toxic to bacteria

6. Humoral Innate Defenses1. Phagocytes:Neutrophilsbecome phagocytic when find infectious materialFixed & Wandering Macrophagesfrom monocytes 2. Natural Killer Cellsin lymph

7.

8. phagocytosisphagocyte must adhere to pathogen in order to ingest itbacteria with external capsules elude captureOpsonins: proteins released by immune cells that coats the capsules (opsonization)  phagocytes can capture them

9. Natural Killer Cellsnonspecific killers of any cell w/out “self” cell surface markerstravel through body patrolling for: virus-infected cell cancer cellsNot phagocyticinduce target cell  apoptosissecrete potent chemicals that enhance inflammatory response

10.

11.

12. Inflammatory Responsetriggered when tissues injured by: physical trauma intense heat irritating chemicals infection by viruses, fungi, or bacteria

13. Inflammatory Responsebeneficial effects:prevents spread of damaging agents to nearby tissuesdiposes of cell debris & pathogensalerts adaptive immune responsesets stage for repair*ultimate goal: clear injured area of pathogens, dead tissue cells, other debris so tissue can be repaired

14. Cardinal signs of acute inflammationRednessHeatSwellingPain

15.

16. Inflammatorychemical release1st step: “chemical alarm”chemicals released by: injured or stressed cells immune cells mast cells  histaminemacrophages recognize type of invader using surface receptors called TLRs and release specific chemical in response  triggers release of cytokinesother chemicals released: kinins prostaglandeins complement

17.

18. Inflammatory response:Vascular changesvasodilation  hyperemia (congestion with blood)  2 of cardinal signs: redness & heatincreased permeability = exudate  other 2 cardinal signs: swelling (edema), paincapillaries allow fluid containing clotting factors & antibodies  swelling  pain

19.

20.

21. Acute  chronicinflammationmacrophages predominant cell cleaning up cell debris @ sites of prolonged or chronic inflammationpus: mixture of dead or dying neutrophils, damaged or dead tissue cells, living & dead pathogensif inflammatory response has failed to clear area collagen fibers may be laid down  walling off area  abscess: may require surgical drainage to heal

22. Nonspecific antimicrobial proteins1. Interferonssecreted by cells in response to viral invasionnot viral specifichelp nearby cells make proteins that interfere with viral replication2. Complement provides major mechanism for destroying foreign substances in bodyreleases inflammatory chemicalslyses & kills certain bacteria

23. feverabnormally high body temperaturepyrogens: chemicals released by neutrophils & macrophages  alters thermostat in hypothalamusadaptive response that benefits body:liver & spleen sequester iron & zinc making them less available to support bacterial growthincreases metabolic rate of tissue cells in general

24. https://www.khanacademy.org/science/health-and-medicine/human-anatomy-and-physiology/introduction-to-immunology/v/inflammatory-response

25. Adaptive Defensesbody‘s built -in specific defense system3 features:SpecificSystemicMemory 2 parts1. Humoral or antibody-mediated immunity B Cells2.Cellular or cell-mediated immunityT Cells

26. antigens1. complete antigens2. incomplete antigensFunctions:Immunogenicity: ability to elicit certain lymphocytes to proliferate (multiply)Reactivity: ability to react with activated lymphocytes & the antibodies released

27. Lymphocytes of adaptive immunityB lymphocytesmake antibodies humoral immunitymature in bone marrowT lymphocytescellular immunitymature in thymus1. Immunocompetenceability of immune cells to recognize (by binding) to specific agns; recognition implies presence of plasma membrane receptors2. Self-tolerance

28.

29. Antigen-presenting cellsAPCsengulf agns  present fragments of them onto their cell-surface markersmajor types:Dendritic cellsMacrophagesB cells

30.

31. Dendritic cellsmost important APC (only job they have)internalize agn  migrate to nearest lymph node  present agn to T cells

32. Macrophages present agns to T cells in order to be activated by effector T cells  release chemicals that in turn activate the macrophage  increases their phagocytic activity

33. B cellsdo not activate naïve T cells like dendritic cells or macrophagesonly present to T helper cells in order to get help for their own activation

34.

35. Activation & differentiation of B Cellsonce activated, most of the clone members become effector cells = plasma cellsplasma cells secrete antibodiesrest become memory cellshttp://web.biosci.utexas.edu/psaxena/MicrobiologyAnimations/Animations/HumoralImmunity/micro_humoral.swf

36. Immunological MemoryMemory cells capable of mounting a rapid attack against the same antigen in any later encounters (secondary immune response)Memory B cells provide humoral immunological memory

37. http://web.biosci.utexas.edu/psaxena/MicrobiologyAnimations/Animations/HumoralImmunity/micro_humoral.swf

38.

39. Active & passive humoral immunityActive Passive acquired during 1st exposure to agn:InfectionVaccinationprovides memoryacquired throughinjection of abys into bodypassage of abys from mother  fetus in uteropassage of abys to newborn in breastmilk*NO MEMORY

40. Vaccinations Immune system exposed to harmless version of pathogen triggers active immunitystimulates immune system to produce antibodies to invaderrapid response if future exposureMost successful against viral diseases

41. Jonas SalkDeveloped first vaccineagainst polioattacks motor neurons 1914 – 1995April 12, 1955Albert Sabin1962oral vaccine

42. Antibodies (ABYs)4 polypeptide chains2 heavy chains2 light chainsheld together by di-sulfide bonds

43. Antibody structure constant areas determine function & aby classvariable area enable recognition of specific agn

44. 5 classes of abysIg M: 1st aby secreted from plasma cell during 1◦ response, potent agglutinatorIg A: found in body secretions: saliva, sweat, milk, blocks attachment of agns to mucous membranesIg D: functions as B cell membrane agn receptorIg G: most #’s in plasma, main aby of 1◦ & 2◦ responses, only 1 to cross placentaIg E: binds to mast cells & basophils  release histamine, levels rise during allergic rx or chronic parasitic infections of GI tract

45.

46. http://highered.mheducation.com/sites/0072507470/student_view0/chapter22/animation__the_immune_response.html

47. Monoclonal abyspure preparations (a clone) of a single aby typeuseful in diagnostic testspregnancySTDsHepatitis treating some types of cancerLeukemiaLymphomas

48.

49. 2007-2008What if the attacker gets past the B cells in the blood & actually infects some of your cells?You need trained assassins to kill off these infected cells!TAttackof the Killer T cells!

50. Cellular Immune responseagn presentation to T cells  provokes cellular immune response2 major populations of T cells (based on which of 2 surface proteins a mature T cell displays:; both  memory cells:CD4 = helper T cells: THactivate B cells, macrophagesdirect adaptive immunity (does not happen w/out THCD8= cytotoxic T cells: TCdestroy any cell in body that has anything foreign in it

51. T cell responsestimulateB cells &antibodiesYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYkillerT cellactivatekiller T cellsorinterleukin 1interleukin 2interleukin 2infected cellhelperT cellhelperT cellhelperT cellhelperT cellhelperT cellactivatedmacrophage

52. Attack of the Killer T cellsKiller T cellbinds toinfected cellDestroys infected body cellsbinds to target cellsecretes perforin proteinpunctures cell membrane of infected cellinfected celldestroyedcell membraneKiller T cellcell membranetarget cellvesicleperforin puncturescell membrane

53. http://highered.mheducation.com/sites/0072507470/student_view0/chapter22/animation__t-cell_dependent_antigens__quiz_2_.html

54. Immune responsefree antigens in bloodantigens on infected cells humoral responsecellular response B cellsT cellsmacrophages(APC)helperT cellsplasmaB cellsmemoryB cellsmemoryT cellscytotoxicT cellsYYYYYYYYantibodiesYYYskinskinpathogen invasionantigenexposure

55. Organ transplants&rejection preventioncell-mediated responses reject grafts & foreign transplants unless the recipient is immunosuppressedinfections are major complications

56. grafts

57. immunodeficienciesSCIDSevere Combined Immunodeficiencygroup of genetic disorders deficit of functioning T and B cells untreated:fataltx:bone marrow transplantacquired immunodeficiencies1.Hodkins lymphoma2. AIDS

58. HIV & AIDSHuman Immunodeficiency Virusvirus infects helper T cellshelper T cells don’t activate rest of immune system: T cells & B cellsalso destroy T cellsAcquired ImmunoDeficiency Syndromeinfections by opportunistic diseasesdeath usually from other infectionspneumonia, cancer

59. Autoimmune Diseasesoccurs when the body regards its own tissues as foreign & mounts an immune attack against itRheumatoid arthritisGraves diseaseHashimoto’s thyroiditisMultiple sclerosisCeliac diseaseLupus (SLE)

60.

61.

62. hypersensitivitiesabnormal reaction to otherwise harmless agnimmediate hypersensitivityallergies/ Ig E abysubacute hypersensitivity: abys & complement3. delayed hypersentsitivity:cell-mediated

63. Key attributes of immune system4 attributes that characterize the immune system as a wholespecificityantigen-antibody specificitydiversityreact to millions of antigensmemoryrapid 2° responseability to distinguish self vs. non-selfmaturation & training process to reduce auto-immune disease

64.