Describe the role of positive & negative feedback | Homework Help

Things to know or review: 1. Describe the role of positive & negative feedback in the regulation of the immune response. Compare the 3 lines of immune defense, what happens to our immune response to pathogens if one line of defense fails? 2. Can the presence of non-pathogenic bacteria on our skin or mucous membranes reduce our infections with pathogens? Compare the chemical & physical defenses in keratinized membranes (skin) with mucous membranes (lining the mouth, airways…). What event may trigger the release of interferon from cells? Describe interferon’s effects. 3. Which white blood cells provide non-specific immunity? What stem cell develops into these WBCs? Where are they produced? 4. Describe the actions of basophils & mast cells in starting an inflammation response. Describe the symptoms of inflammation & what changes in the blood flow at an infection cause those symptoms. Describe how positive chemotaxis attracts WBCs to an infection. 5. Compare the 2 major types of phagocytic cells. What other effects do each of these phagocytes have on the immune responses? Describe the process of phagocytes’s. What happens if pathogens evade them? 6. Describe the actions of natural killer (NK) cells. What substance do they release to kill cancerous or virally infected cells? 7. Where are complement proteins made? Where are they found prior to activation? What signal(s) activate complement proteins? Describe how complement can kill bacteria & how it activates other parts of the immune system. 8. Describe the symptoms of a fever & recovery phase. What are its risks & benefits? 

Things to know or review: 1. Define pathogen. Do pathogenic organisms belong to a single group or are they widely scattered across the “tree of life”? How does this affect the challenge of preventing infectious disease? 2. Explain the SA/V advantages for small pathogens. Explain virulence. Are all microbes pathogenic? 3. Describe the arms race hypothesis in terms of the co-evolution of a pathogen & its host. What does it tell us about our ability to eliminate infectious diseases? 4. Why do insect-transmitted & water-transmitted diseases show higher rates of virulence than human-human directly transmitted diseases? How might pathogen virulence change if we limit insect transmission & had clean water? 5. What are the leading causes of infectious deaths in developing countries? Which infectious diseases have the largest impact on child survivorship worldwide? 6. Compare viruses, bacteria, and protists for relative size, relative genome size, who has both DNA & RNA, a diploid genome, organelles that are present, capable of asexual reproduction, and which may have intracellular life stages. 7. Trace the steps in a virus life cycle: viral entry to cell, viral DNA or RNA enters ,v2nyucleus, translation of viral proteins, assembly of virus, buIDing or lysis of cell. 12