1. The Immune System

2. When we are sick, our bodies respond
When we are sick, our bodies respond. Think of a recent time when you were ill. What was wrong? What did you feel like? How did your body react? With this in mind… what do you think the function of the immune system is, and what might happen if it does not work well?

3. What is it? The body's defense system against germs and other invaders
Made up of special cells, proteins, tissues, and organs

4. Three Lines of Defense First Line Second Line Third Line
Act as barriers to prevent pathogens from entering body
Second Line
Act when tissues are injured or damaged
Signs and symptoms letting you know you are sick
Third Line
Act to destroy and
remove pathogens

5. First Line Skin Mucus membranes
Tissues that protect the interior surfaces of the body that may be exposed to pathogens
Secrete MUCUS—a sticky fluid that traps pathogens

6. Second Line Tears/saliva/sweat Fever Gastric juices Pain
Contain lysozome—an enzyme that breaks down the cell wall of certain pathogens
Fever
Chemicals are released, increasing body temp. Heat kills pathagens
Gastric juices
Pain

7. Third Line
Macrophages
Lymphocytes
Antibodies
Lymph Nodes
Vaccines

8. Macrophages Pac-man like white blood cells (WBCs)
Consume and destroy pathogens

9. Lymphocytes Specialized WBCs that activate the immune response
Helper T-cells
Detect the virus and alert the Killer Ts and B-cells
Killer T-cells
Release chemicals to destroy pathogens
B-cells
Make antibodies

11. Antibodies “Lock” into pathogen (antigen) and destroy it
Remain in the blood stream in case the same germ(s) come back
Antibodies at work...

12. Lymph Nodes
Trapping stations that help assist in destroying the infection

13. Vaccine
Small or weakened dose of the pathogen (antibodies), given to activate the immune response