Biology 140- Anatomy & Physiology | |||
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Lines of Defense Okay, our bodies have three lines of defense. Their names are really easy to remember, becuase they're just named 1st, 2nd, and 3rd. 1st Line of Defense: Physical and Chemical Barriers These defenses are nonspecific and innate. Examples: skin, mucous membranes, hair, cilia, saliva (enzymes), tears, perspiration (lysozymes), sebaceous glands (oil), gastric juices, vaginal secretions, earwax, and urine flow. 2nd Line of Defense:okay, there are four things for this category, so I'll try to organize them the best I can on this site. I. Antimicrobial Proteins
(A) They attach themselves to an invader (pathogen) and flag down T-cells and B-cells . (B) They create holes in bacteria (damage) so that cytoplasm leaks out. II. Natural Killer Cells (NKCs) and Phagocytes
III. Inflammation: redness, swelling, heat, and pain.
IV. Fever
3rd Line of Defense = Specific Immunity (1) Antigens-things that the body identifies as "foreign" and stimulate an immune response (production of anitbodies.
(2) Lymphocytes T-cells- work via direct attack on a pathogen, or become plasma cells to produce antibodies. B-cells- become plasma cells, which produce antibodies. Immunological Memory-The first time you are infected with something, it might take your body days to mount a response to it. Any subsequent infections of the same pathogen may only take hours to create a response against. This is because of the presence of memory B-cells.
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