Tuesday, 22 November 2011

2.60b Lymphocytes

Describe how the immune system responds to disease using white blood cells, illustrated by phagocytes ingesting pathogens and lymphocytes releasing antibodies specific to the pathogen.

Unlike Phagocytes, Lymphocytes has a large nucleus.
  • Each type of bacteria has a particular Lymphocyte that can detect it.
  • This is a specific indentification by Lymphocyte of the bacteria. If there was a different bacteria it would require a different Lymphocyte.
  • When they come together, the cell divides to form two different clones and these are called memory cells. The other clones (the Plasma cells) which are produced are the ones that are going to produce the anti-bodies. All genetically identical to the first one.

  • The Plasma cells secrete protein molecules into the bloodstream which are called anti-bodies. One possible action for an anti-body is that it will attach to bacterial cell and act as a label that will attract phagocytes. Second mechanism is that the anti-body attaches and causes bacterial lysis and kills the bacteria. The third more of action, is causing many bacterias to stick together and this is called Aggrototination. This means that the Phagocytes can then engulf the bacterias

  • If after the infection, we meet the same type of bacterial cell The chances of it meeting the memory cell is greater than meeting the original cell and so the consequence of this is is that it reacts faster and more anti-bodies. This is called the seconday response which means the Plasma Cells are the primary response.

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