1. Aim: How does the immune system work? Do Now:What does this picture tell you? Pathogens Living organisms that cause diseases; for example, Bacteria Viruses Fungi Parasites

2. Your BodiesThree lines of defense 1) Physical (skin and mucous membranes), 2) Immune Cells or WHITE BLOOD CELLS in the BLOOD! PHAGOCYTES or big eaters/MACROPHAGES 3) WBCs called Lymphocytes (T cells and B cells)

3. Immune cells: Called white blood cells or lymphocytes are of 3 types

4. Three types of lymphocytes Macrophages (the ‘big eaters’) T cells and B cells There are different types of T cells and B cells

5. T cells B cells Different types of T and B cells Helper T cell Killer T cell Plasma B cells Memory B cells

6. What is Immune System? ? Protects you against billions of bacteria, viruses, and other parasites. It is made up of your first line of defense _______________ and WBCs _________________________

7. Differences between the different types of Immune cells ( or white blood cells) Macrophages (the ‘big eaters’) They attack the invader first… they can’t really recognize the type of invader though… When they get tired of eating they call for help… They call upon T cells and B cells who work little different…strategically The first ones to respond are the helper T cells

8. Helper T cells Helper T cells are the major driving force and the main regulators of the immune defense. Their primary task is to activate B cells and killer T cells. First step they take is to recognize the enemy…look at the bar code.. Or __________ However, the helper T cells themselves must be activated.

9. How does our body recognize a foreigner/invader? Marker protein on the pathogen, the foreigner Invader Antigen Barcode on the foreigner… Antigen is a protein marker on the foreign substance

10. How? On the surface of each lymphatic cell (T cell and B cell) are receptors that enable them to recognize foreign substances. These receptors are very specialized – match only one specific antigen. The body makes many different types of lymphocyte cells so that the immune system can recognize nearly all invaders. Could be a T or a B cell

11. What makes your immune cells recognize the foreigner? A foreigner is recognized by the presence of ANTIGEN on its surface. T and B cells have receptors to recognize the antigen

12. Hey, but someone has to tell the helpers that invader is here… Who calls upon them? Macrophages..or phagocytes How do they inform the Helpers/ or activate the helpers?

13. So the helper T cells themselves must be activated…

14. B Cells The B cell now needs helper T cells to become activated. When this happens, the B cell starts to divide to produce clones of itself. During this process, two new cell types are created, plasma cells and B memory cells. Plasma cells make antibodies against the antigen

15. What are antibodies? Y-shaped proteins made by ____________ ______________ against the _____________________

17. But the really cool thing about the immune system is that it has the ability to "remember" enemies that it has fought in the past. If the immune system detects a "registered" invader, it will strike much more quickly and more fiercely against it. As a result, an invader that tries to attack the body a second time will most likely be wiped out before there are any symptoms of disease. When this happens, we say that the body has become immune.

20. i protect you against billions of bacteria, viruses, and other parasites. Am a foreign substance that triggers a reaction from the immune system. Am found on the surfaces of bacteria and viruses. Am microscopic organism that causes sickness

22. I need a host cell. I hijack body cells! I trick my host into producing more of myself… I can’t reproduce on my own.