The Immune System

1. The Immune System

2. History of Medicine 1857 1883 1928 1955 Today Germ Theory Louis Pasteur hypothesizes that disease is caused by small organisms.

3. History of Medicine Koch’s Postulates Robert Koch finds 4 conditions that prove a pathogen causes a disease. 1857 1883 1928 1955 Today Germ Theory Louis Pasteur hypothesizes that disease is caused by small organisms.

4. History of Medicine Koch’s Postulates Robert Koch finds 4 conditions that prove a pathogen causes a disease. 1857 1883 1928 1955 Today Antibiotics Sir Alexander Fleming discovers penicillin. Germ Theory Louis Pasteur hypothesizes that disease is caused by small organisms.

5. History of Medicine Koch’s Postulates Robert Koch finds 4 conditions that prove a pathogen causes a disease. Polio Vaccine Jonas Salk’s vaccine against polio becomes available. Discontinued in the U.S. in 1994. 1857 1883 1928 1955 Today Polio Comeback! Worldwide efforts increase to vaccinate people against polio. Antibiotics Sir Alexander Fleming discovers penicillin. Germ Theory Louis Pasteur hypothesizes that disease is caused by small organisms.

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

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

8. 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

9. 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

10. 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

11. Transmission • How can pathogens be transferred? • Indirect contactdoes NOT REQUIRE touching an infected individual. • Touching an infected surface • Breathing in infected air • Drinking contaminated water • Direct contactREQUIRES touching an infected individual. • Kissing • Hand shaking • Sexual intercourse

12. Transmission Through Vectors • Defined: 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

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

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

15. 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

16. 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

17. 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 • T cells destroy infected cells • B cells produce antibodies, which deactivate the pathogen.

18. phagocyte Blood stream bacteria phagocyte

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

20. 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

21. 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

22. 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

23. Immunity • In all types of immunity, pathogens are destroyed before you get sick. • Passive immunity occurs withoutan immune response. • Mother’s milk • Genetics • Active immunity occurs after aspecific immune response. • Having chicken pox • Acquired Immunity occurs after given a vaccine. • Flu shot

24. Vaccination • Prevents infections (not a cure) • Vaccination process • Weakened/dead pathogen or antigens are 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

25. 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? • What is the skin’s role in immunity? • How can pathogens be transferred? • Who hypothesized that disease is caused by small organisms? • Which pathogen… • Absorbs nutrients from living tissue? • Are prokaryotic? • What is the vector of malaria? • What are the differences between passive, active, and acquired immunity? • How do vaccines work?