Presentation on theme: "The Immune System Small Pox A white blood cell eating bacteria."— Presentation transcript:
1 The Immune SystemSmall PoxA white blood cell eating bacteria.
2 The Immune SystemSlide # 2The immune system is a defense system against foreign invaders (pathogens)Immune system consists of a variety of different types of white blood cells (WBC’s)White blood cell eating bacteria
3 The SKIN: The First Line of Defense Slide # 3The SKIN: The First Line of Defense1. The skin is the most important first line of defensea. Top layer is dead cells; prevents pathogens from enteringb. Sweat & tears have enzymes that prevent bacterial growth2. Mucus that lines the nose, throat, & lungs traps pathogens3. Pathogens and mucus are swept into stomach where stomach acids destroy themLayers of Skin
4 Inflammatory Response: Second line of Defense Slide # 4Inflammatory Response: Second line of DefenseNonspecific response to a localized infection.Injured or infected cells cause blood vessels to enlarge so they can leak fluid & WBC’sa. skin appears red at injury siteb. swelling occurs around infection3. Macrophages (large WBC’s are first to arrive)a. Nonspecific: treat all pathogens the sameb. Consume (eat) dead cells & pathogens4. Fever kills pathogens. Fever over 103°F is dangerous for humans.
5 White blood cell chasing a bacterium cell Click on the picture to watch!
6 The Inflammatory Response Slide # 6 The Inflammatory ResponseWoundSkinPhagocytes move into the area and engulf the bacteria and cell debrisBacteria enter the woundCapillary
7 The Immune Response: Vocabulary Slide # 7The Immune Response: Vocabulary1. Immunity: capacity of the human body to resist specific pathogens by identifying foreign (non-self) antigens2. Antigen: anything that causes an immune response3. Lymphocytes: WBC’s involved in immunity and the immune responsea. Helper T cells, B cells, & Killer T cellsb. are specific; seek out & destroy specific pathogens4. Immune Response: specific response to a infection that has spread through body triggered by the presence of antigens/pathogens
8 The Immune Response: The Third and Final Line of Defense Slide # 81. Macrophages ingest pathogen; send out chemical signal to call Helper T cells to the site of infection2. By the time Helper T cells arrive, macrophages have incorporated pathogen’s antigens onto its own cell membrane3. Helper T cell attaches to antigens on macrophage & develops new binding site that recognizes foreign antigens (copies enemy’s information)4. Helper T cell passes information to two different attack cells: B cells & Killer T cells
9 Immune Response T cell binds to activated macrophage Slide # 9Immune ResponseT cell binds to activated macrophageHelper T cell activates killer T cells and B cellsMacrophageHelper T CellKiller T CellT CellT cell, activated by macrophage, becomes a helper T cellInfected CellAntigens are displayed on surface of macrophageKiller T cells bind to infected cells, disrupting their cell membranes and destroying them
10 Killer T Cells: Have Direct Contact with Antigens Slide # 10Killer T Cells: Have Direct Contact with Antigens1. Killer T cells come into direct contact w/ a cell; pierces hole in cell walla. Water moves into the cell & the cell swells & bursts open2. Killer T cells produced at same time as B cells3. Killer T cells destroy protists, virus infected cells, & cancer cells
11 B Cells Produce Antibodies Slide # 11B Cells Produce AntibodiesB cells release antibodiesMillions of B cells are cloned & millions of antibodies are released into blood when fighting infectionAntibody: Y shaped protein that “tags” an antigen for destructionAntibodies also bind to virus & bacterial toxins & neutralizes themAntigen-binding sitesAntibodyAntigenAntibodyAntigen
12 Active vs. Passive Immunity Slide # 12Passive Immunity is acquired when antibodies to the antigen are injected into the body. They do not last. (Ex. Breast milk)Active immunity is produced when the body creates its own antibodies after being exposed to an antigen.Acquired through vaccinationsAcquired through infection of pathogen.Antibodies are constantly produced by memory cells created when the body was first infected.
13 Why you don’t get chicken pox twice. Interval between exposuresFirst exposureSecond exposureTimeAntibody Concentration
14 Immune System Disorders/Problems Slide # 14An allergy is a disorder in which the immune system overreacts to the presence of an antigen such as pollen.An autoimmune disease is one in which the immune system attacks its own body cells. Ex. M.S. and ArthritisRejection of organ transplants (cells are foreign).Cancer cells are naturally destroyed by the body; however, when the body fails to recognize them they spread causing tumors.
15 Cells of the Immune System The body's innate defense against disease is natural immunity. The immune system consists of white blood cells, cell products, and other substances.
16 Cells of the Immune System 1. Lymphocytes include:a. T cells (T for thymus, where they mature)b. B cells (B for bone marrow, where they originate)c. Natural killer (NK) cells (less abundant)2. Macrophages & Granulocytes: Phagocytic or "cell-eating”a. Neutrophils -- form an early line of defense against bacterial infections (Non-specific response) & involved in inflammatory responseb. Eosinophils -- Their natural role is to defend us against parasites; also release chemicals that damage lungs and contribute to asthmac. Basophils -- involved in inflammatory response & allergic reactionsd. Mast cells settle in connective tissues and usually do not circulate in the blood stream. Release histamine; contributes to allergic reactionsMast cell with Salmonella bacteria