Transcript Slide 1
CHAPTER 12: BODY DEFENSES Roots: Immun = free Lyse = to break Phago = eat anti = against Macro = large Tox = poison Foreign Substance = anything not endemic to the body Pathogens = harmful or disease-causing microorganisms A. Nonspecific Defense System = immediate response to any threat 1. 2. 3. 4. skin mucous membranes inflammatory response proteins B. Specific Defense System (Immune System) = attacks specific threats 1. immune cells (lymphocytes and macrophages) 2. special molecules Nonspecific Defense First Line of Defense Surface Membrane Barriers: 1. Acid pH of skin and vaginal secretions – kill bacteria. 2. Stomach HCl and enzymes – kill pathogens. 3. Saliva and lacrimal fluid (tears) containing lysozymes – kill bacteria. 4. Digestive and respiratory tract mucus traps pathogens. 5. Nonspecific Nonspecific Defense First Line of Defense (cont.) Phagocytes: Cells that eat foreign particles. (Nonspecific) 1. macrophage = large phagocyte 2. neutrophils = blood born phagocyte Use lysosomes (vacuoles with digestive enzymes) to digest particles once they are inside the phagocyte body. Nonspecific Defense First Line of Defense (cont.) Natural Killer Cells (NK cells): 1. “police” the body looking for intruders. 2. Can lyse and kill cancer and virus-infected cells. 3. Can respond to ANY intruder. (nonspecific) biotechnologie.de Nonspecific Defense Inflamm = set on fire Second Line of Defense Inflammatory Response: 1. Nonspecific 2. Four cardinal signs of acute inflammation: a. Redness b. Heat c. Swelling d. Pain Nonspecific Defense Second Line of Defense INJURY! Damaged cells Release inflammatory chemicals (kinins, histamine) Blood vessels dilate Capillaries Leak Clotting proteins Increased blood flow Edema (fluid in tissue) Neutrophils Monocytes Dead cell/pathogen clean up Second Line of Defense Nonspecific Defense Clotting proteins Increased blood flow REDNESS HEAT Increases metabolic rate Edema (fluid in tissue) SWELLING More nutrients & O2 Dead cell/pathogen clean up PAIN Fibrin barrier Limited movement HEALING Viruses 1. Cannot make their own ATP or proteins 2. Invade and take over host body cells so they can reproduce. 3. Cells cannot save themselves, but work to save the body by producing INTERFERONS (small proteins that go to other cells and bind to the membrane receptors blocking virus entry.) uk.polylooks.com Fever = abnormally high body temperature Pyrogens = chemicals secreted by white blood cells and macrophages that cause a rise in body temperature. When a fever is good: Bacteria require iron and zinc. During a fever the liver hoards these minerals. Fever also increases the metabolic rate which delivers nutrients, white blood cells, etc. to the damage zone. When a fever is bad: If a fever gets too high it causes a “scrambling” of enzymes and other body proteins. http://www.youtube.com/watch?v=wGVoMMo1KW8 Immune Response Pg 375 in text. Antigen = receptors on the surface of cells (both harmful cells and body cells). Cytotoxic cell = releases destructive chemicals (cytotoxins). Memory cell = retains information identifying pathogens that have been fought before. Antibodies = inactivate antigens by 3 methods: 1. neutralization = antibodies bind to bacterial exotoxins or to viruses and block harmful effects. 2. agglutination = mismatched blood or bacteria clumps. 3. precipitation = settling out of unwanted particles.