Cards (8)

  • Phagocytes
    1. Neutrophils - produced in the bone marrow -innate and secrete cytokines to attract phagocytes. Multilobed nucleus and grainy.
    2. Macrophages - produced in the bone marrow - innate
    3. Monocytes - Kidney shaped nucleus
  • Lymphocytes
    Have large nucleuses and smaller than phagocytes.
    1. T cells - Mature in the thymus gland. Helper, Killer, Regulatory, Memory. Cell mediated immune response.
    2. B cells - Mature in bone marrow. Plasma and Memory. Humoral immune response.
  • Phagocytosis - non specific
    1. Chemicals attract the phagocyte to the pathogen.
    2. Phagocytes recognises the pathogen as a 'non-self' cell
    3. Phagocyte engulfs the pathogen by endocytosis and is surrounded by a vacule - Phagosome.
    4. Phagosome combines with lysosome containing digestive enzymes forming a phagolysosome.
    5. Digestive enzymes break down the pathogen and waste is removed by exocytosis.
  • Phagocytosis - Specific

    • Phagocytosis is done by a macrophage
    • Antigens from the broken down pathogen bind to maceophage antigens forming a - Histocompatibility complex (MHC)
    • Display antigens on the plasma membrane and becomes an APC - Antigen presenting cell.
  • Specific immune response
    1. Antigen from pathogen or APC are present
    2. Detected by
    • T lymphocytes - cell mediated
    • B lymphocytes - humoral
  • Cell mediated response
    • APC has antigens complemetry to receptor on t helper cell which stimulates the immune response - Colonal selection
    • Cloning by mitosis of the T cell and then differentiation into different t cells. - T helper, T regulator, T killer cells. - Colonal expansion and differentiation.
  • Humoral response
    • In response to pathogens
    • Activated T helper cells bind to pathogen receptors on b cells - colonal selection
    • Activated T cell release interleukins which activate other b cells.
    • B cells rapidly divide by mitosis into - B plasma cells and B memory cells. - Colonal expansion.
    • Plasma cells produce specific and complementary antibodies which bind to the antigens, disabling them.
  • Secondary response
    If the body is infected by the same pathogen again B memory cells rapidly divide into B plasma cells
    • Much faster response as primary response is skipped.