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The Immune System

The Immune System. Pathogens. Defined: microorganisms that cause disease Viruses : turn cells into virus making factories. Pathogens. Defined: microorganisms that cause disease Viruses : turn cells into virus making factories Bacteria : prokaryotes that can release toxic chemicals.

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The Immune System

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  1. The Immune System

  2. Pathogens • Defined: microorganisms that cause disease • Viruses: turn cells into virus making factories

  3. Pathogens • Defined: microorganisms that cause disease • Viruses: turn cells into virus making factories • Bacteria: prokaryotes that can release toxic chemicals

  4. Pathogens • Defined: microorganisms that cause disease • Viruses: turn cells into virus making factories • Bacteria: prokaryotes that can release toxic chemicals • Fungi: pierce cells and absorb the nutrients

  5. Pathogens • Defined: microorganisms that cause disease • Viruses: turn cells into virus making factories • Bacteria: prokaryotes that can release toxic chemicals • Fungi: pierce cells and absorb the nutrients • Protozoans: single cells protista (eukaryotes) Plasmodium causes malaria

  6. Pathogens • Defined: microorganisms that cause disease • Viruses: turn cells into virus making factories • Bacteria: prokaryotes that can release toxic chemicals • Fungi: pierce cells and absorb the nutrients • Protozoans: single cells. Protists (eukaryotes) • Parasites: grow and feed on a host tapeworms

  7. Transmission • Some carried by wind, water, direct contact, indirect contact… • Vectors: organism that carries a pathogen Examples: • Malaria – mosquitos carry the protozoan • Black Death – carried by fleas of mice • West Nile Virus – carried by birds, but spread by mosquitoes

  8. The Skin • 1st line of defense: physical barrier • Oils & sweat destroy some pathogens • Some pathogens burst…some shrivel bacteria bacteria Skin

  9. Mucus Membranes • Coat the openings of the body • Nose, mouth, ears, eyes, genitals, anus • Lined with cilia & sticky fluids to trap pathogens

  10. YouTube Clip: Types of White Blood Cells (phagocytes) from the BBC YouTube Clip: Types of White Blood Cells (lymphocytes) from the BBC White Blood Cells • Job: Search & destroy

  11. YouTube Clip: Types of White Blood Cells (phagocytes) from the BBC YouTube Clip: Types of White Blood Cells (lymphocytes) from the BBC White Blood Cells • Job: Search & destroy • Type 1: Phagocytes • surround & engulf invaders by phagocytosis

  12. YouTube Clip: Types of White Blood Cells (phagocytes) from the BBC YouTube Clip: Types of White Blood Cells (lymphocytes) from the BBC White Blood Cells • Job: Search & destroy • Type 1: Phagocytes • surround & engulf invaders by phagocytosis • Type 2: Lymphocytes • create antibodies & destroy infected body cells

  13. phagocyte Blood stream bacteria phagocyte

  14. Defense Proteins • Antibodies • Created & released by lymphocytes • Attach to antigens (like handcuffs) antibody Y Y Y Y Y lymphocyte Y Y Y

  15. Defense Proteins • Antibodies • Created & released by lymphocytes • Attach to antigens (like handcuffs) • How do they kill? • Causes pathogens to clump • Weakens the cell membrane of the pathogen

  16. B CELLS MAKE ANTIBODIES ANTIBODIES ATTACH TO ANTIGENS OF THE PATHOGEN Blood Stream B B B B Y Y Y Y Y Y Y Y Y Y Y Y phagocyte Y Y Y B B Y Y Y Y Y Y Y Y ANTIBODIES CAUSE THE PATHOGENS TO CLUMP TOGETHER PHAGOCYTE DESTROYS PATHOGENS

  17. Defense Proteins virus Virus RNA New virus New virus New virus New virus Interferon Interferon Interferon New virus Infected! Not Infected! • Interferon • Cell becomes infected by virus • Infected cell sends interferon to healthy neighbors • Interferon causes healthy cell to create defense enzymes • Healthy cell able to fight virus

  18. Vaccination • Prevents infections (not a cure) • Vaccination process • Weakened pathogen is injected • Immune system produces… • Antibodies to fight the weakened pathogen • Memory cells for future infections • Goal: Speed up immune response if you encounter the actual virus

  19. Review • Which part of our immune system coats the openings of the body? • How do lymphocytes differ from phagocytes? • What are antibodies and how do they help keep us from harm? • Which pathogen… absorbs nutrients from living tissue? are prokaryotic? • Which illness is spread by mice? • What is the vector of malaria?

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