2PathogensAre organisms or particles such as bacterium, fungus or viruses that have potential to cause disease.Your body is under constant attack from these pathogens
3Your immune system tries to prevent these attacks and restore homeostasis It has three lines of defense
4First line of DefenseSkinMucous membraneSalivaBlocks entry into your body
5Counter attacks The second line of defense Now the pathogen has slipped through the first line and now your body counterattacks.
6Some cells attack invaders Macrophages: a type of white blood cell that kills bacteria one at a time by ingesting them. They travel through the blood streamNeutrophils: another type of white blood cell that release a bleach like chemical to kill any bacteria
7Natural Killer T cells: attack only cells that have been infected by microbes, not the microbes themselves. (lead attack against viruses)
8Proteins that punch holes into bacteria once activated ComplementsProteins that punch holes into bacteria once activated
9Inflammation response You get cutArea releases chemical signalsIt gets red and inflames because this increases blood flowIt promotes migration of the second line of defense
10Raise body temperature When the counter attack occurs these white blood cells send messages to the brain to increase body temperature to try to prevent the growth of the pathogen
11Now the third line you are sick Two types of response to different pathogens.Antibody-mediated response (bacteria)Cell mediated response (virus) cell is infected (produces killer T cells)
12Antigens: are present on the surface of a pathogen the body then can recognize itself from nonself
13Antibodies: Produced by plasma B cells they bind to antigens causing a clumping effect and flag others to eat them….