First line of defense nonspecific barriers physical and

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 • Neutrophil • Eosinophil • Basinophil Agranulocytes • Lymphocyte • Monocyte Phagocytes (engulf and destroy bacteria) Kills parasitic worms, destroys antigen-antibody complexes Releases heparin (anti-coagulant) and histamine, which prevents inflammation. Involved in the immune response. Includes B cells and T cells. Phagocytosis 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!

Pathogen infects human. This pathogen contains ______ antigens that mark it as an invader. A white blood cell (phagocyte) recognizes the pathogen as an invader and engulfs it through ________. phagocytosis T activates The phagocyte ______ Helper T cells. The phagocyte now displays the pathogen antigen from the ________. Y Y Y Helper T cells activate B cells which then produce antibodies ________. Y Y Y B Y Y These antibodies attach to the pathogen and signal for them to be 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): 1. 2. Granulocytes • Neutrophil • Eosinophil • Basinophil Agranulocytes • Lymphocyte • Monocyte Phagocytes (engulf and destroy bacteria) Kills parasitic worms, destroys antigen-antibody complexes Releases heparin (anti-coagulant) and histamine, which prevents inflammation. Involved in the immune response. Includes B cells and T cells. Phagocytosis 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!

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 _______. Y Y Y Helper T cells activate B cells which then produce _________. Y Y B Y These antibodies attach to the pathogen and signal for them to be _____. Antigen: _________________________ Antibody: _________________________________________________ Vaccine: _________________________ Pathogen: _________________________