1. The IMMUNE SYSTEM The Body’s Defenses Intro 2009: Swine Flu
..\..\..\..\COURSES\AP BIO\articles\Diseases and conditions\2009 Swine Flu most updated.doc

2. Defense against pathogens
Pathogen = an organism or virus that causes a disease.
Infectious disease = a disease caused by a pathogen.
Streptococcus pneumoniae
Giardia

3. Bacteria vs. Viruses Bacteria Prokaryote CELLS Living Have metabolism
Not cells
Not living
No metabolism
Consist of nucleic acid surrounded by a protein coat
Bird flu

4. Exit Questions
Create a Venn diagram showing at least 3 differences and 1 similarity between bacteria and viruses (4 points)
Last unit we discussed mechanisms of evolution. Explain how the influenza virus changes over time, resulting in different strains.
(2 points)

5. Bacteria vs. Viruses: Treatment and Defense
Antibiotics
Fight Bacteria only, NOT Viruses
Antibiotics attack bacterial metabolism
Your immune system defends against bacteria and viruses.
Killer microbe (also on desktop “cool videos”) F:\Desktop\Cool Videos
Some antiviral medications are available, but usually you have to let the illness pass on its own.

6. Exit Questions
Explain what a pathogen is, giving at least 3 examples. (4 points)
Imagine you are a doctor. Explain to an imaginary patient why you won’t treat the common cold (a viral illness) with antibiotics. (2 points)

7. Vectors! A vector is an organism that transmits a pathogen…
Ex. The mosquito is a vector for malaria
Video…

8. The Body’s Defenses!

9. Lines of Defense Nonspecific Defense Mechanisms……
1. Nonspecific Defense (aka innate immunity)
2. Specific Defense (aka acquired immunity)
Nonspecific Defense Mechanisms……

10. Nonspecific Defense Mechanisms……
1st and 2nd lines of defense…
Skin and mucous membranes
Skin acidity/ dryness
Mucus—traps pathogens
Lysozyme (in tears, saliva, mucus)– enzyme digests cell walls of bacteria
Stomach acidity
Nonspecific Phagocytic and Natural Killer Cells
Inflammation
Blood clotting
Protective proteins
(ex. Interferons are proteins that protect cells from viruses)

11. Exit Questions
Explain how the skin acts as a nonspecific defense from infectious disease and how the malaria parasite gets past this nonspecific defense. (4 points)

12. Specific Immunity Recognizes specific pathogens Involves:
Antigen: a foreign molecule that causes a response by lymphocytes
Where might you find an antigen?
Antibodies: proteins in body that fight pathogens by binding to antigens. Very specific.
White Blood Cells

13. Overview of specific immune responses
C:\Documents and Settings\BBAUGHMAN\Desktop\bio powerpoints\Chapter 39 BDOL IC
Animations: Animation of immune system OK…but not great

14. Antibody Action
C:\Documents and Settings\BBAUGHMAN\Desktop\bio powerpoints\Chapter 39 BDOL IC
Shows pathogens docking on a cell and then shows antibodies attaching to pathogen and preventing entry. Then white blood cell destruction of pathogenhttp://catalog.nucleusinc.com/generateexhibit.php?ID=15529

15. Types of White Blood Cells
Phagocytes (Macrophages): Eat pathogens by endocytosis and present antigens to other white blood cells.
T lymphocytes:
Helper T cells: help activate B cells and “killer” T cells
Cytotoxic T cells (“killer T cells): destroy infected cells.
B lymphocytes: Produce antibodies
Memory Cells
B or T cells that “remember” the antigen.
C:\Documents and Settings\BBAUGHMAN\Desktop\bio powerpoints\Chapter 39 BDOL IC

16. Helper T Cell, Cytotoxic T cell Activity

17. Exit question
Outline the roles of each of the following in specific immunity:
Macrophages
Helper T cells
B Cells
Killer T cells
Antibodies
Antigens
(6 points)

18. Immune Responses
Primary immune response: Production of lymphocytes and antibodies the 1st time the body is exposed to an antigen
Secondary immune response: stronger, faster immune response if the individual is exposed to the same antigen at some later time~ Immunological memory

19. How to get immune: Active Immunity = due to exposure to antigen
produces a primary response. Produces memory cells for the disease.
by recovering from disease
Vaccination

20. Vaccination: Benefits Discussion
Discussion: Benefits:
Epidemic/pandemic/death prevention
Eradication of fatal/debilitating diseases (ex. smallpox)
Reduced disability due to diseases (ex. Blindness and deafness in babies due to rubella infection of their unvaccinated mothers.)
Vaccines = carefully tested for safety.
Serious adverse reactions (allergic) are very rare.
Dangers:
Some controversial concerns… (discussion)
“The medical and scientific communities have carefully and thoroughly reviewed the evidence concerning the vaccine-autism theory and have found no association between vaccines and autism.”
Citation:

21. Exit question Explain how vaccination works. (2 points)
Will a vaccination work as a cure for a person that is already infected with a disease? Why or why not? (2 points)

22. AIDS Caused by HIV (human immunodeficiency virus)
Infects several types of white blood cells
Weakens the immune system
Reduces the # of active lymphocytes
inability to produce antibodies.

23. Exit Question
Explain how HIV affects the immune system and how AIDS kills (3 points).

24. Magic School Bus Evaluation
Watch Season 1: Episode 3
Evaluate how the immune system was presented in "The Magic School Bus."  Was the representation accurate?   Which details were left out?   Which details were explained well?   Explain and justify your answers.

25. Optional Material follows

27. Discuss cause, transmission, social implications.
UN Article on AIDS orphans (2004)
Same article in word document