Non-specific immunity

• What is an infection?

  An interaction between a pathogen and the body's various defence mechanisms.
• What is immunity?


  When the body's defence mechanisms are better prepared to deal with a pathogen due to it being their second time dealing with it.
• What is the first step of phagocytosis?

  Chemicals produced by the pathogen and by body cells under attack ,e.g. histones, act as attractants, causing phagocyted to move towards the pathogen.
• What is the second step of phagocytosis?

  Receptors on the phagocytes cell-surface membrane recognise and attach to chemicals on the surface of the pathogen.
• What is step three of phagocytosis?

  They engulf the pathogen to form a vesicle, known as a phagosome.
• What is step four of phagocytosis?

  Lysosomes move towards the vesicle and fuse with it to form a phagolysosome.
• What is step five of phagocytosis?

  Enzymes called lysozymes are present within the lysosome. These lysozymes destroy ingested bacteria by hydrolysis of their cell walls.
• What is step six of phagocytosis?

  The soluble products from the breakdown of the pathogen are absorbed into the cytoplasm of the phagocyte.
• What two ways other than cell recognition does our body defend against pathogens?

  Preventing the entry of pathogens by a variety of physical and chemical defences e.g. the skin, mucous membranes, tears and saliva.

  Inflammation (swelling and heating) of the region invaded by the pathogen, a process known as a non-specific inflammatory response.
• What are phagocytes?


  white blood cells
• Where are phagocytes produced?

  In the bone marrow.
• What are the two main types of phagocyte?

  Neutrophils and macrophages
• What are the two main types of phagocytes?

  Neutrophils and macrophages
• What is the role of phagocytes?

  To recognise and engulf pathogens- phagocytosis
• What is the first step of phagocytosis known as?

  Chemotaxis
• What is it called when a phagocyte engulfs a pathogen?

  endocytosis
• What can be done with the products of the pathogen after it's digested?

  They can be displayed on the cell surface of the phagocyte to trigger the specific immune response.
• What kind of phagocytes present antigens on their cell surface membrane?

  Macrophages