The Immune System

1. The Immune System Our Personal Cleaning Army!

2. What comes to mind when you think of the immune system? • Staying healthy • YOUR PERSONAL ARMY! • This army trains to fight against foreign invaders like bacteria and viruses.

3. The Front Line… • Skin • Oil and sweat kill bacteria on the surface of the body • Tears and saliva kill bacteria in eyes and mouth • Mucous in nose, mouth, and lungs trap bacteria from entering the body.

4. What happens when an invader enters the body? • White blood cells (PHAGOCYTES) fight the battles at the site of infection. • These are the soldiers of your army! • They eat bacteria and cells infected by viruses. • Neutrophils bleach and kill bacteria • Pus (a interferon chemical) alerts white blood cells to get moving!

5. PHAGOCYTES Eats bad bacteria!

6. PHAGOCYTES WHITE BLOOD CELLS

7. What happens if the foreign invaders get deep into the body? • The body can recognize that a substance is not its own-these foreign bodies are called ANTIGENS! • The body sends out its spies, the B cells, to identify the invader and produce antibodies to fight it. • B cells are called “memory cells” because they remember the antigen.

8. How the B cells work…

9. Primary vs Secondary Response • During the primary response, it takes a few days for the B cells to respond and produce a large number of antibodies. • During the secondary response, large numbers of antibodies are produced rapidly because the B cells recognize the antigens. VS

11. The Immune System Wins!