Defence systems: Infection and response: Biology: GCSE (9:1)

• Non-specific defence

  A general defence that works the same against all pathogens
• Immune system

  The cells and tissues that recognize and attack foreign substances in the body
• White blood cell

  A blood cell that fights disease

  
• Phagocytosis

  When a white blood cell called a phagocyte engulfs a pathogen to destroy it with enzymes

  
• Antibody


  A protein that binds to a specific antigen and triggers the pathogens to be destroyed

  
• Antibody production

  When a white blood cell called a lymphocyte produces antibodies
• Antitoxin


  A substance that neutralises the poisonous products of microorganisms

  
• Antimicrobial secretions


  Secretions from the skin and nose that reduce bacterial growth
• Barrier

  A physical body defence such as skin that prevents pathogens entering the body

  
• Mucus


  A thick and sticky substance produced by goblet cells in the body, traps invasive pathogens and particles
• Cilia


  The hair-like projections on the outside of trachea cells that move mucus and other substances away from the lungs

  
• Stomach acid

  Hydrochloric acid in the stomach that kills pathogens

  
• Enzymes

  Certain enzymes in the body such as lysozymes found in tears are capable of destroying pathogens

  
• Antigen


  A substance on a foreign cell or pathogen that triggers an immune response

  
• Phagocyte


  The white blood cell responsible for phagocytosis via ingestion

  
• Lymphocyte


  The white blood cell responsible for antibody and antitoxin production

  
• Platelets


  Structures in the blood responsible for blood clotting, prevents further bleeding and reduces the chances of pathogens entering the blood, can also bind to pathogens