Phagocytosis

• What is phagocytosis an example of?

  Non-specific defense mechanism (response is immediate and the same for all pathogens)
• What is a pathogen?

  Any microorganism that causes disease (e.g bacteria, viruses, fungi, protozoa)
• What is phagocytosis?

  The ingesting of large particles into vesicles by the cell surface membrane
• Process of Phagocytosis

  1. Phagocyte is attracted go the pathogen by chemoattractants. It moves towards the pathogen down a concentration gradient
  2. The phagoctye binds to the pathogen
  3. The phagocyte engulfs the pathogen, forming a phagosome
  4. Lysosomal in the phagocyte migrate to the phagosome and fuse with it
  5. The lysosomes release hydrolytic enzymes into the phagosome and hydrolyse the pathogen
  6. The breakdown products of bacterium are absorbed by the phagocyte
• What allows phagocytosis to recognise and attach to chemicals on the surface of a pathogen?

  Receptors on the cell-surface membrane
• How do phagocytes become APCs?

  After a phagocyte englufs and hydrolyses a pathogen, it can present the pathogens antigens on its surface