First line of defense (non-specific barriers) :

1. First line of defense (non-specific barriers): physical and chemical barriers that prevent pathogens from entering (skin, mucus, acids in the stomach, etc.) This barrier is non-specific because it will exist no-matter-what.

2. Second line of defense • (non-specific white blood cells): leukocytes are white blood cells. They are non-specific because they will react to any foreign invader. • INFLAMMATION: Damaged tissue’s leukocytes cause blood vessels to dilate and the area becomes RED. Fluid builds up, causing SWELLING and PAIN. • Phagocytes and monocytes eat foreign invaders.

3. Third line of defense: (specific antigens/antibodies): 1. The pathogen or foreign invader has ANTIGENS on the surface of it’s structure. 2. White blood cells called lymphocytes recognize a foreign invader because of its ANTIGENS and will cause our B cells (types of lymphocytes, white blood cells) to begin to make proteins called ANTIBODIES. 3. ANTIBODIES have a special molecular form that allows them to match ANTIGENS like a puzzle piece. 4. Once attached, the invader can be destroyed! Some B cells can remember an antigen and produce antibodies quicker next time!

4. Pathogen infects human. This pathogen contains ___________ that mark it as an invader. A white blood cell (phagocyte) recognizes the pathogen as an invader and engulfs it through ________________. antigens phagocytosis T activates The phagocyte ____________ Helper T cells. The phagocyte now displays the antigen from the _______________. pathogen B Y Y Y Y Y Y Y Y Y Y Helper T cells activate B cells which then produce _______________. antibodies These antibodies attach to the pathogen and signal for them to be ___________. destroyed

5. VOCABULARY Antigen: marker on pathogens that signal for the production of antibodies. Antibodies: proteins that are found in the blood that detect and destroy invaders. Vaccine: a weakened or dead pathogen that is injected into a organism to stimulate the immune system and the production of antibodies. Pathogen: Any bacteria or virus that can cause disease.

6. First line of defense (non-specific barriers):

7. Second line of defense (non-specific white blood cells): 1. 2.

8. Third line of defense: (specific antigens/antibodies): 1. The pathogen or foreign invader has ANTIGENS on the surface of it’s structure. 2. White blood cells called lymphocytes recognize a foreign invader because of its ANTIGENS and will cause our B cells (types of lymphocytes, white blood cells) to begin to make proteins called ANTIBODIES. 3. ANTIBODIES have a special molecular form that allows them to match ANTIGENS like a puzzle piece. 4. Once attached, the invader can be destroyed! Some B cells can remember an antigen and produce antibodies quicker next time!

9. THIRD LINE OF DEFENSE: SPECIFIC IMMUNE RESPONSE Pathogen infects human. This pathogen contains ___________ that mark it as an invader. A white blood cell (phagocyte) recognizes the pathogen as an invader and engulfs it through _________________. T The phagocyte _________ Helper T cells. The phagocyte now displays the antigen from the ______________. B Y Y Y Y Y Y Y Y Helper T cells activate B cells which then produce _________________. Y Y These antibodies attach to the pathogen and signal for them to be _________. Antigen:__________________________________________________ _________________________________________________ Antibody: _________________________________________________ _________________________________________________ Vaccine: __________________________________________________ _________________________________________________ Pathogen: _________________________________________________