1. The Immune System

2. Louis Pasteur hypothesizes that disease is caused by small organisms.
History of Medicine
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.
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.
History of Medicine
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.
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 contact does NOT REQUIRE touching an infected individual.
Touching an infected surface
Breathing in infected air
Drinking contaminated water
Direct contact REQUIRES 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 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. White Blood Cells Job: Search & destroy
YouTube Clip: Types of White Blood Cells (phagocytes) from the BBC
White Blood Cells
YouTube Clip: Types of White Blood Cells (lymphocytes) from the BBC
Job: Search & destroy

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

17. White Blood Cells Job: Search & destroy Type 1: Phagocytes
YouTube Clip: Types of White Blood Cells (phagocytes) from the BBC
White Blood Cells
YouTube Clip: Types of White Blood Cells (lymphocytes) from the BBC
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 Y Y Y Y Y Y Y Y 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 B B B B B 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 B Y Y B Y Y Y Y Y Y Y Y
ANTIBODIES CAUSE THE PATHOGENS TO CLUMP TOGETHER
PHAGOCYTE DESTROYS PATHOGENS

22. Defense Proteins 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
Virus RNA
New virus
New virus
New virus
New virus
Interferon
Interferon
Interferon
New virus
Infected!
Not Infected!

23. Immunity
In all types of immunity, pathogens are destroyed before you get sick.
Passive immunity occurs without an immune response.
Mother’s milk
Genetics
Active immunity occurs after a specific 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 antibodies 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?