Nonspecific External Barriers skin, mucous membranes

Transcription

1 Immune system Chapter 36 BI 103 Plant-Animal A&P Levels of Defense Against Disease Nonspecific External Barriers skin, mucous membranes Physical barriers? Brainstorm with a partner If these barriers are penetrated, the body responds with Innate Immune Response phagocytic and natural killer cells, inflammation, fever If the innate immune response is insufficient, the body responds with Adaptive Immune Response cell-mediated immunity, humoral immunity Fig

2 The Protective Function of Mucus Bacteria trapped by mucus and cilia Fig Levels of Defense Against Disease Nonspecific External Barriers skin, mucous membranes If these barriers are penetrated, the body responds with Innate Immune Response phagocytic and natural killer cells, inflammation, fever If the innate immune response is insufficient, the body responds with Adaptive Immune Response cell-mediated immunity, humoral immunity Fig

3 Innate Immunity: The Infantry White blood cells (leukocytes) specialized for different tasks carry out all immune responses a. Phagocytes eat foreign cells neutrophils, macrophages dendritic cells b. Natural Killer (NK) cells attack the body s own cells dead cell layer epidermis Innate immunity: The Inflammatory Response 1 Tissue damage carries bacteria into the wound 2 Wounded cells release chemicals (red) that stimulate mast cells dermis 3 Mast cells release histamine (blue) 4 Histamine increases capillary blood flow and permeability 5 Phagocytes leave the capillaries and ingest bacteria and dead cells Fig

4 Innate Immunity: Fever Macrophages release pyrogen (protein which raises temp) Increased activity of phagocytic white blood cells Slows down bacterial reproduction (Fe deficiency) Cells of immune system grow rapidly Levels of Defense Against Disease Nonspecific External Barriers skin, mucous membranes If these barriers are penetrated, the body responds with Innate Immune Response phagocytic and natural killer cells, inflammation, fever Adaptive Immunity: How does remembering a specific pathogen aide in the immune response? If the innate immune response is insufficient, the body responds with Adaptive Immune Response cell-mediated immunity, humoral immunity Fig

5 Levels of Defense Against Disease Cells: Nonspecific External Barriers skin, mucous membranes If these barriers are penetrated, the body responds with Innate Immune Response phagocytic and natural killer cells, inflammation, fever If the innate immune response is insufficient, the body responds with Adaptive Immune Response cell-mediated immunity, humoral immunity Fig The Lymphatic System thymus bone marrow thoracic duct spleen lymph vessels lymph nodes valve prevents backflow lymph node chambers packed with white blood cells Fig

6 Acquired Immunity Passive Immunity Acquired by the transferring of antibodies from an immunized animal to a susceptible one. Only lasts while the antibodies are in the blood stream. Few weeks at best Colostrum passes antibodies to newborns 6

7 Acquired Immunity Result of exposure to pathogenic organisms or immunizations after birth. Active Immunity Acquired through direct contact with specific disease causing organism. Body develops antibodies to counteract the invasion. Develops after the disease or vaccination. Long-lived and often life long. Aquired /adaptive immunity 1.Passive Immunity 2.Active Immunity 1.Antibody mediated 2.Cell mediated 7

8 Antibody mediated Antibody Mediated Immunity Antigen protein molecule which causes an antibody response Antibody protein molecule produced in the bloodstream that neutralizes a specific antigen. 8

9 Antibody antigen Structure light chain heavy chain Variable regions form antigen binding sites Constant regions are the same in all antibodies of a given type Fig Step 1: B Cell selection and then clonal expansion Pathogen 9

10 Step 2: B cell differentiation T cell B cell differentiation Step 3: Antigen Elimination 10

11 Step 4: Memory B cells Antibodies Can Serve as Receptors or Effectors macrophage B cell antibody antigen antibody antigen (a) Antibody receptor function (b) Antibody effector function Fig

12 Acquired /adaptive immunity 1.Passive Immunity 2.Active Immunity 1.Antibody mediated 2.Cell mediated Cell mediated 12

13 Step 1: T cell antigen recognition Helper T cell Cytotoxic T cell If cell infected with a virus Step 2: After recognition, the T cells will grown and multiply Step 3: Antigen Elimination Cytotoxic T cell 13

14 NK and Cytotoxic T Cells Kill cells with viral antigens on cell surface; perforin and proteases puncture cells and kill them by apoptosis Step 3: Antigen Elimination Helper T cell type Cytokinin type and affect 14

15 Natural Killer Cells Cytokines secreted by helper T cells also stimulate natural killer (NK) cell division Unlike cytotoxic T cells, NK cells can kill infected cells that are missing all or part of their MHC markers Step 4: Memory T cells develop Helper T cell Cytotoxic T cell 15

16 Interactions Between Antibody-Mediated and Cell-Mediated Responses Cells of the Immune System Phagocytes: Neutrophils Macrophages Dendritic cells Self Recognition Cells: NK Cells **Non-specific response** Secretory Cells Eosinophils Basophils Mast Cells **Non-specific, innate immune response** Adaptive Cells T cells B cells **Antibody mediated immune response** 16