Phagocytosis

• What is the body's first line of defense?

  It's physical or chemical barriers.
• What is the body's second line of defense?

  White blood cells.
• What are the two types of white blood cell?

  Phagocytes and lymphocytes.
• What do phagocytes do?

  Ingest and destroy pathogens by a process called phagocytosis.
• What are lymphocytes involved in?


  Immune responses.
• Why does the phagocyte move toward the pathogen?

  The phagocyte is attracted to the chemicals produced by the pathogen.
• What do phagocytes have on their cell-surface membrane?


  Receptors.
• What do the receptors on the phagocyte do?

  They recognize and attach to the chemicals on the surface of the pathogen.
• What do phagocytes do once they attach to the chemicals on the surface of the pathogen?

  They engulf the pathogen to form a vesicle known as a phagosome.
• What do lysosomes within the phagocyte do?

  Migrate towards the phagosome and fuse with it.
• What do lysosomes release into the phagosome?

  Lysozymes.
• What do lysozymes do?

  Destroy ingested bacteria by hydrolysing their cell walls.
• What happens after the breakdown of the pathogen?

  Its soluble products are absorbed into the cytoplasm of the phagocyte.