Immunology

• T lymphocytes


  Cells involved in cell-mediated immunity
• T lymphocytes are produced in the bone marrow and migrate to the thymus gland to mature
• T Cell receptor


  Attaches to antigens on the surface of cells
• Each unique T lymphocyte has a unique T Cell receptor
• Situations where T lymphocytes can recognize antigens

  • Cell infected with a virus
  • Cell is a mutated cancer cell
  • Transplanted cell or tissue
  • Macrophage engulfs a pathogen
• Antigen presenting cells


  • Cells that display antigens on their surface for T lymphocytes to recognize
• T helper cells


  T lymphocytes that carry out a range of functions
• T helper cell activation

  1. Attaches to antigen presented on cell surface

  2. Undergoes mitosis to produce clones

  3. Produces cytokines (interleukins)

  4. Can activate cytotoxic T cells
• Cytotoxic T cells (T killer cells)


  Identify and destroy abnormal or infected cells
• T memory cells


  Long-lived T cells that can rapidly differentiate into cytotoxic T cells if the same pathogen is encountered again
• T regulator cells


  Down-regulate the immune system once a pathogen has been destroyed, and help prevent autoimmune disorders
• Inflammation


  A response to injury or infection where the area becomes hot, red and swollen as a result of increased blood flow
• Inflammation is caused by

  Mast cells secreting histamine
• Histamine release causes


  1. Increased blood flow in capillaries

  2. Capillaries to leak more so fluid enters tissues and causes swelling

  3. Phagocytes to leave the blood and enter the tissue

  4. The release of cytokines
• Phagocytosis


  The process of a phagocyte engulfing a pathogen or other foreign material
• Phagocytosis


  1. Phagocytes engulf the pathogen once it has been identified

  2. Phagocytes can digest / destroy pathogens once they engulf them
• Certain types of phagocyte (macrophages)

  • Can present the antigens on their surface and become antigen-presenting cells
• Antigen-presenting cells


  Trigger the antibody mediated immunity and cell mediated immunity response
• Finding the correct / complementary antigen and receptors

  Takes a relatively long time compared to the antigen response
• 1. cells


  1. Need to find antigens on the surface of pathogens that have complementary shapes to their receptors on their cell membranes

  2. Then need time to produce antibodies that are complementary / specific to the antigens on the surface of pathogens
• Identify one of the two stages of the body’s response to a soft tissue injury.

  • involuntary inflammatory response (1)

  • proliferation phase (1).