Defence against disease

• What are pathogens?

  Disease carrying microorganisms
• Name four types of pathogens.

  Virus, bacteria, fungi, protozoa
• Who discovered the importance of hand washing?

  Semmelweis
• What did Snow discover about cholera?


  It was caused by pathogens
• What are the primary defenses against pathogens?

  Skin and mucous membranes
• How do skin and mucous membranes protect against pathogens?

  They act as chemical and physical barriers
• What is the outer layer of the skin like?

  Tough, dead, and waterproof
• What role does sebum play in skin defense?


  Controls fungal and bacterial growth
• Why is the skin kept dry?

  To discourage pathogen growth
• How does the skin remove pathogens?

  By continually shedding its surface layer
• What is the role of mutualistic bacteria on the skin?


  They prevent pathogenic growth
• What are mucous membranes?

  Areas of skin kept soft with mucus
• Where can mucous membranes be found?

  Nose, trachea, vagina, urethra
• What do lysozymes in mucus do?


  Damage bacterial cell walls and kill bacteria
• What is the purpose of the blood clotting cascade?

  Prevents blood loss and pathogen entry
• What happens when blood vessels are damaged?

  They are exposed to air
• What do platelets release during clotting?

  Clotting factors
• What is prothrombin converted to?


  Thrombin
• What is fibrinogen converted to?

  Insoluble fibrin fibers
• How do fibrin fibers contribute to clotting?

  They tangle to form a mesh
• What do the fibers in a clot trap?

  Red blood cells
• What forms a scab?

  The clot dries
• How are the innate and adaptive immune systems related?

  They are interconnected
• How does the innate immune system respond?

  To broad pathogen categories
• What is phagocytosis?

  Engulfing of pathogens by phagocytes
• What forms when a phagocyte engulfs a pathogen?

  A phagosome
• What do lysosomes do in phagocytosis?

  Join phagosome to form phagolysosomes
• What do phagolysosomes secrete?

  Digestive enzymes
• What are lymphocytes?

  White blood cells that target pathogens
• What do helper T lymphocytes do?

  Activate beta lymphocytes
• What do beta lymphocytes produce?

  Antibodies
• What are antigens?

  Glycoproteins on plasma membranes
• What triggers antibody production?

  Antigens
• How are antibodies produced?

  In response to specific antigens
• What happens during antibody production?

  Macrophage presents pathogen components
• What activates beta lymphocytes?

  Receptor binding with T lymphocytes
• What do activated beta lymphocytes proliferate into?

  Plasma cells and memory cells
• What do plasma cells produce?

  Specific antibodies
• What do memory cells do?

  Induce a secondary immune response
• What blood type produces anti-B antibodies?

  Type A