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Human A&P Chapter 21 – The Immune System. Our Defense Systems b Our body has two means of defense against pathogens and toxins Innate or non-specific.

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Presentation on theme: "Human A&P Chapter 21 – The Immune System. Our Defense Systems b Our body has two means of defense against pathogens and toxins Innate or non-specific."— Presentation transcript:

1 Human A&P Chapter 21 – The Immune System

2 Our Defense Systems b Our body has two means of defense against pathogens and toxins Innate or non-specific defensesInnate or non-specific defenses –External body membranes –Internal non-specific defenses Adaptive defenses or specific immunityAdaptive defenses or specific immunity b My Analogy – 3 walls of defense b Differences: SpecificitySpecificity MemoryMemory

3 Non-specific Defenses b External Barriers (1 st Wall) Skin and mucous membranesSkin and mucous membranes SecretionsSecretions –lactic acid and fatty acids (skin) –mucus: filter for respiratory system, etc. –Tears, lysozyme, stomach acid Normal floraNormal flora

4 Non-specific Defenses (cont.) b 2 nd wall - Internal Defenses (cells and chemicals) Natural Killer (NK) CellsNatural Killer (NK) Cells Phagocytes – what cells would this be?Phagocytes – what cells would this be? –Figure 21.1

5 Non-specific Defenses (cont.) b Inflammatory Response (inflammation) Signs and symptoms?Signs and symptoms? Pathogens and tissue damage stimulate the release of inflammatory chemicalsPathogens and tissue damage stimulate the release of inflammatory chemicals –histamine, cytokines, and others These result in:These result in: –Vasodilation –Increased vascular permeability –Attraction of phagocytes Why would this be a good thing?Why would this be a good thing? Figure 21.3Figure 21.3

6 Non-specific Defenses (cont.) Pus and abscessesPus and abscesses b Interferons – anti-viral proteins Figure 21.4 and CD animationFigure 21.4 and CD animation

7 Non-specific Defenses (cont.) b Complement Proteins - blood proteins that bind to bacteria and kill them –Figure 21.5 and CD animation

8 Non-specific Defenses (cont.) b Fever – pyrogens stimulate an increase in body temperature Reading AssignmentReading Assignment

9 Specific Immunity b Final Wall of Defense Also called the immune responseAlso called the immune response Produced by the B-cells and T-cellsProduced by the B-cells and T-cells b Key features: SpecificitySpecificity –B-cells and T-cells recognize foreign molecules or antigens (Ag) MemoryMemory –they remember which antigens have entered the body

10 Specific Immunity (cont.) b Antigens – Antibody-generating substances Immunity is all about recognizing self from non-selfImmunity is all about recognizing self from non-self “if you’re not with us, you’re against us”“if you’re not with us, you’re against us” Figure 21.6 and other figureFigure 21.6 and other figure

11 Specific Immunity (cont.) b Activation of Lymphocytes (B-cells and T-cells) Ag binding to the receptor starts activationAg binding to the receptor starts activation –A second signal must then be given Once the cell is activated it:Once the cell is activated it: –Proliferates and –Carries out its function

12 Specific Immunity (cont.) b There are 2 types of responses: Cellular or Cell-mediated immunity is directed against intracellular antigensCellular or Cell-mediated immunity is directed against intracellular antigens –Cytotoxic T-cells Humoral or Antibody-mediated immunity is directed against extracellular antigensHumoral or Antibody-mediated immunity is directed against extracellular antigens –B-cells

13 Cell Mediated Immunity b There are 2 types of T-cells: Activated Cytotoxic T-cells kill virus- infected cells and tumor cellsActivated Cytotoxic T-cells kill virus- infected cells and tumor cells –Figures 21.16, 21.18, CD animation, and drawing on board

14 Cell Mediated Immunity Activated Helper T-cells help B-cells and Cytotoxic T-cells become activatedActivated Helper T-cells help B-cells and Cytotoxic T-cells become activated –They give the 2 nd signal Figure 21.17Figure 21.17

15 Antibody Mediated Immunity b Antibody Mediated Immunity How does a B-cell become activated?How does a B-cell become activated? –Ag and Helper T-cells Figure 21.17Figure 21.17

16 Antibody Mediated Immunity The cell proliferatesThe cell proliferates some of the new cells (plasma cells) will produce antibodies (Ab)some of the new cells (plasma cells) will produce antibodies (Ab) –Ab will bind to the Ag and lead to its destruction some of the new cells will become memory cellssome of the new cells will become memory cells Figure 21.9 and AMAZING animationFigure 21.9 and AMAZING animation

17 B-cell Activation Antigen B-cell

18 B-cell Activation

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22 Helper T-cell

23 B-cell Activation

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29 Memory Cell

30 Antibody Mediated Immunity b Memory The primary (or 1 st ) response to an antigen takes 3-6 days to take effectThe primary (or 1 st ) response to an antigen takes 3-6 days to take effect secondary response takes only hourssecondary response takes only hours Chickenpox example and Figure 21.10Chickenpox example and Figure 21.10

31 Antibody Mediated Immunity b Ab Classes – Table 21. 3

32 Antibody Mediated Immunity b Ab Functions – Figure 21.13

33 Immunizations b What does an immunization do? b A vaccine is made from antigens that are not harmful Leads to memoryLeads to memory b CD animation

34 Allergies b Allergies are an immune response to a harmless substance b Hay fever is an allergy to plant pollen this usually results in the release of large amounts of histamine from white blood cellsthis usually results in the release of large amounts of histamine from white blood cells histamine triggers inflammation as well as runny nose, sneezing, etc.histamine triggers inflammation as well as runny nose, sneezing, etc. treated with an antihistamine (it blocks the effects of histamine)treated with an antihistamine (it blocks the effects of histamine) b Anaphylactic shock

35 Autoimmunity & Transplants b Autoimmunity - the immune system reacting against normal body proteins rheumatoid arthritis, others on page 819rheumatoid arthritis, others on page 819 b Transplant Rejection Why are transplanted organs or tissues rejected?Why are transplanted organs or tissues rejected?

36 Chapter 21 Readings b Articles


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