1. Immune System

2. How does your body defend itself from foreign invaders?
A typical sneeze.

3. Learning Target: Distinguish between specific and nonspecific defenses and provide examples of each.
First Line of Defense - barriers to pathogens (?)
(organisms that cause disease)
What barriers do you see in the picture?
1. Skin
Mucous membranes, Ear wax , Hair

4. - backup when invaders breach the skin
Second line of defense
- backup when invaders breach the skin
1. Chemical barriers
  a. Enzymes
-proteins
 -found in body fluids, tears and
perspiration
  -produce chemicals that are
inhospitable to pathogens  

5. Second line of defense
Chemical barriers
b. Interferons
  -proteins often
produced in the liver
  -block replication of viruses

6. Second line of defense 2. Fever -Reduces iron in blood (bacteria and fungi need iron to survive) -Phagocytic cells attack better in high temperatures

7. Second line of defense 3. Inflammation- increased blood flow to an area (results in heat, redness, swelling) a. fluids wash away toxins b. Neutrophils destroy invading organisms

8. Inflammatory Response

9. Second line of defense 4. Phagocytosis a
Second line of defense 4. Phagocytosis a. Macrophages engulf particles before they reach the blood stream

10. The first line of defense and second line of defense are Nonspecific lines of defense What does this mean? A response to any type of invader.

11. Third Line of Defense The immune process
Develops the 3rd month after conception
3rd month after conception
A. 3rd month after the sperm and egg unit
B. 3rd month after delivery of a baby

12. Third line of defense
Stem cells in bone marrow form
lymphopoietic cells
Look at the picture in your notes. What 2 types of lymphocytes are being produced?
a. some pass through the thymus and
become T-lymphocytes, locating in the
nodes, spleen and thymus
b. some become B-lymphocytes and settle in
lymph nodes, spleen and bone marrow

14. Third line of defense Becomes functional after birth The third line of defense is specific What does this mean? A particular pathogen will be recognized and targeted for destruction.

15. The Immune System Story
1. Before birth, body cells inventory the proteins and other large molecules in the body, learning to recognize these as “self”.

16. The Immune System Story
2. “Non-self”, foreign organisms or molecules migrate into the body. Some invaders, such as viruses, come across their target cells and attach to them. Then they enter the cells and use them to reproduce.

17. The Immune System Story
3. Macrophages engulf the foreign object they encounter, destroying them. The antigens of the invaders are displayed on the surface of the macrophages.

18. The Immune System Story
4. Macrophages head for the lymph vessels and lymphoid tissue. Upon their arrival, Helper T-cells activated the Killer T-cell and B-cells.

19. The Immune System Story
5a. Cell-mediated (CMI)- Killer T-cells enter the circulatory system and search for and destroy foreign antigens. 5b. Antibody-mediated immunity (AMI)- B-cells produce antibodies to attach to invaders antigens, thus disabling them.

20. The Immune System Story
6. Suppressor T-cells stop the action of the immune system when the invaders have been destroyed.

21. The Immune System Story
7. Some B-cells and Killer T-cells become memory cells. If the same invader enters the body again, the immune system is ready.

22. "The immune system: an explanation"
Watch this video Link