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.

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. 1.INFLAMMATION: Damaged tissue’s leukocytes cause blood vessels to dilate and the area becomes RED. Fluid builds up, causing SWELLING and PAIN. 2.Phagocytes and monocytes eat foreign invaders. Granulocytes NeutrophilPhagocytes (engulf and destroy bacteria) EosinophilKills parasitic worms, destroys antigen-antibody complexes BasinophilReleases heparin (anti-coagulant) and histamine, which prevents inflammation. Agranulocytes LymphocyteInvolved in the immune response. Includes B cells and T cells. MonocytePhagocytosis Monocytes are the chief phagocytes. They circulate in the blood for 1–2 days before entering body tissues to become macrophages.

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!

T B 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 ________________. The phagocyte now displays the antigen from the _______________. The phagocyte ____________ Helper T cells. Helper T cells activate B cells which then produce _______________. These antibodies attach to the pathogen and signal for them to be ___________. antigens phagocytosis activates pathogen antibodies destroyed

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.

First line of defense (non-specific barriers) :

Second line of defense (non-specific white blood cells) : Granulocytes NeutrophilPhagocytes (engulf and destroy bacteria) EosinophilKills parasitic worms, destroys antigen-antibody complexes BasinophilReleases heparin (anti-coagulant) and histamine, which prevents inflammation. Agranulocytes LymphocyteInvolved in the immune response. Includes B cells and T cells. MonocytePhagocytosis Monocytes are the chief phagocytes. They circulate in the blood for 1–2 days before entering body tissues to become macrophages.

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!

T B 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 _________________. The phagocyte now displays the antigen from the ______________. The phagocyte _________ Helper T cells. Helper T cells activate B cells which then produce _________________. These antibodies attach to the pathogen and signal for them to be _________. Antigen:__________________________________________________ _________________________________________________ Antibody: _________________________________________________ _________________________________________________ Vaccine: __________________________________________________ _________________________________________________ Pathogen: _________________________________________________ THIRD LINE OF DEFENSE: SPECIFIC IMMUNE RESPONSE