1. Chapter 43
The Immune System

2. Videos
Stress, Emotions, and Our Health
NOVA PBS: Immunity Explained

3. Friday – Independent Notes on Chapter 43
Assignment
Friday – Independent Notes on Chapter 43
YOU NEED TO READ THE CHAPTER!!!

4. Let’s Get Defensive! Agenda: Natural Born Killer
Review Notes on Defense
Counting Blood Cells (Activity)

5. Let’s Get Defensive! Agenda: Natural Born Killer
Review Notes on Defense
Counting Blood Cells (Activity)
What’s snot fun about biology? (Activity)

6. The Lymphatic System
Plays an active role in defending the body from pathogens
Network of tissues and organs that help rid the body of toxins, waste and other unwanted materials.
Transport lymph, a fluid containing WBCs

8. How does the first line of defense use chemical barriers?
Innate Immunity
First line defense?
Second line of defense?
How does the first line of defense use chemical barriers?
Hepatitis A and the Stomach
3m
10m

9. 5. Four types of phagocytic WBCs
What are they? 6. How do phagocytic WBCs work? What is the enzyme involved?

10. 7. Interferons
Another set of proteins that provide innate defense against….

11. 8. The Inflammatory Response

12. Adaptive or Acquired Immunity
Specific defense
Works WITH innate immunity
As cells phagocytize microbes, release cytokines to activate other lymphocytes and cells of the immune system
9. Antigen?

13. Acquired Immunity An antigen is any foreign molecule
That is specifically recognized by lymphocytes and elicits a response from them
A lymphocyte actually recognizes and binds
To just a small, accessible portion of the antigen called an epitope
Antigen-
binding
sites
Antibody A
Antigen
Antibody B
Antibody C
Epitopes
(antigenic
determinants)
Figure 43.7

14. Acquired Immunity: Both receive help by helper T cells
The humoral immune response: involves the activation and clonal selection of B cells, resulting in the production of antibodies or immunoglobulins (IG)
The cell-mediated immune response: involves the activation and clonal selection of cytotoxic T cells – target cells like cancer
Both receive help by helper T cells

15. B and T cells recognize antigens.
1 million diff. B
10 million diff. T
A lymphocyte recognizes antigen…
Stimulates and differentiate
One clone short-lived fighters
Other clone memory cells
First time: days
Second time: 2-7 days

16. Antibodies
The five classes of immunoglobulins

17. The role of helper T cells in acquired immunity
Figure 43.15
After a dendritic cell engulfs and degrades a bacterium, it displays
bacterial antigen fragments . A specific helper T cell binds
to the displayed complex. This interaction promotes secretion of cytokines by the dendritic cell.
The cells in this clone
secrete other cytokines
that help activate B cells
and cytotoxic T cells.
Cell-mediated
immunity
(attack on
infected cells)
Humoral
(secretion of
antibodies by
plasma cells)
Dendritic
cell
Bacterium
Peptide antigen
Class II MHC
molecule
TCR
CD4
Helper T cell
Cytokines
Cytotoxic T cell
B cell 1 2 3

18. The Immune System Explained

19. Microscope Activity

20. Tuesday
Immune System Problems
Can You Boost Your Immunity?
Kahoot
FRQ and Peer Review

21. Organ Transplants and Transfusions
The immune system can wage war against cells from other individuals
Transplanted tissues are usually destroyed by the recipient’s immune system
Mismatched antigens
Use medicine to suppress the immune system

22. Allergies
Allergies are exaggerated (hypersensitive) responses to certain antigens called allergens
Perceives harmless substances as dangerous, body tries to fight them off
Releases antibodies, IgE, Release Histamine

23. The allergic response Figure 43.20 IgE antibodies produced in
response to initial exposure
to an allergen bind to
receptors or mast cells. 1
On subsequent exposure to the
same allergen, IgE molecules
attached to a mast cell recog-
nize and bind the allergen. 2
Degranulation of the cell,
triggered by cross-linking of
adjacent IgE molecules,
releases histamine and other
chemicals, leading to allergy
symptoms. 3
Allergen
IgE
Histamine
Granule
Mast cell

24. Age and the Immune System
Researchers believe that aging – leads to a reduction of immune response capability -contributes to more infections, more inflammatory diseases, and more cancer. 
Possible causes:
Atrophying thymus, reduction in T cells
Nutrient deficiency
Less responsive to medications/vaccines
Can’t recognize self from non-self

25. Outgrowing allergies

26. Autoimmune Diseases
In individuals with autoimmune diseases
The immune system loses tolerance for self and turns against certain molecules of the body
Results from hereditary or congenital defects that prevent proper functioning of innate, humoral, and/or cell-mediated defenses
Figure 43.21
Examples:
Rheumatoid arthritis- damage and painful inflammation of the cartilage and bone of joints
Lupus
- Multiple sclerosis
- Insulin-dependent diabetes (Type 1)

27. Stress and the Immune System
Growing evidence shows
That physical and emotional stress can harm immunity
Brain sends stress signals to the endocrine system
Releases hormones for fight/flight
Weakens immune response (Cortisol suppresses inflammation)

28. HIV and AIDs
Highly susceptible to opportunistic infections and cancers that take advantage of an immune system in collapse
Because AIDS arises from the loss of helper T cells
Both humoral and cell-mediated immune responses are impaired
1µm
Figure 43.22