Microbiology

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15-7 Summary

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A significant amount of our bodies attention is devoted to preventing the invasion of the microbes that are living on us. In this chapter we began our journey through the amazing array of compounds, proteins, cells and organs that are part of our immune system. Every tissue and organ in the body has systems that will prevent and eliminate infection and here we looked at the non-inducible part of the system, innate immunity. The two major arms of innate immunity are inflammation and phagocytes. Inflammation is the warning system that alerts the rest of the immune system that something is wrong, while phagocytes are the infantry of our immune system whose job is to clean out whatever is causing the infection. While innate immunity is powerful, many pathogenic microbes have developed defenses against it. In the next chapter we will look at adaptive immunity and how it combines with innate immunity to defeat almost all infectious agents.

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Quickcheck 15-7

Answer the questions below and then hit the Grade Exam button

1. T cell receptors and antibodies

  1. are important proteins on pathogens
  2. are the proteins that recognize antigens
  3. inhibit the immune response
  4. are polysaccharides that recognize antigens

2. Plasma is

  1. the constituents of blood minus the cells
  2. another name for blood
  3. not involved in the immune system
  4. the site that B and T cells originate from

3. Which of the following cells is not a phagocyte

  1. eosinophil
  2. monocytes
  3. macrophage
  4. mast cell

4. Humans could survive without a lymphatic system, since immune cells can get around using the circulatory system.

  1. True
  2. False

5. Which of the following are functions for the spleen

  1. Reservoir for red blood cells
  2. absorbs fat
  3. removes old red blood cells
  4. contains B and T lymphocytes

6. Complement activation can be triggered by just a few antibody:antigen reactions. considering the volume of blood and the need for this signal to travel to the nearest immune cell, how can the binding of the 9 complement proteins be "heard" by the immune system?

7. Some microbes create toxins that prevent ATP formation in phagocytes. This is effective because

  1. it adds energy to the microbe, making it more able to fight the phagocyte
  2. is takes energy away from the microbe making it more able to fight the phagocyte
  3. the depletion of ATP decreases the energy available to the phagocyte and prevents phagocytosis
  4. actually it is not effective, as phagocytes don't need ATP

8. Antibodies have constant regions that react with complement and phagocytes, yet these regions are masked in an unbound antibody, why?

9. Give examples of compounds that attract phagocytes to an area

10. Describe the complement cascade, and the mechanisms that kill microbes

11. Why do you think complement is activated by methods that do not depend upon antibody?

12. Our tissues have all sots of antimicrobial factors in them. Give some examples of them and their mode of action.

13. Describe the steps of phagocytosis. How are microbes killed by phagocytes.

14. Look at Table 15.1, can you see a common theme to the ligands that Toll-like receptors bind? Think about it in terms of self vs. non-self.

15. We cannot contract canine distemper, but we can become infected with rabies. Both of these diseases are caused by viruses. In general terms, can you make an educated guess as to why we are susceptible to rabies, but not distemper?

16. Loss of the ability to make hematopoietic stem cells is fatal. Can you explain why?

17. If you have your tonsils removed, or your spleen, you are more prone to infection. Why?

18. Describe the steps of inflammation and explain how this process is central to our bodies ability to fight infection.