Non-specific Defences Against Pathogens

• What are the four main categories of pathogens?

  Bacteria, viruses, fungi, protoctista
• What is the role of the specific immune system?

  It tailors responses to each pathogen
• How does the specific immune system improve after an infection?

  It becomes more effective against the same pathogen
• What are the characteristics of non-specific defenses?

  • Rapid response
  • Same for all pathogens
  • Prevent pathogen access
• What is the first line of defense against pathogens?

  The skin
• How does the skin protect against pathogens?

  It provides a protective layer with dead cells
• What substance does the skin secrete to protect against bacteria?

  Oily sebum
• What is the effect of the acidic layer formed by sebum?

  It prevents the growth of harmful bacteria
• What do harmless microorganisms on the skin do?

  Reduce the growth of pathogens
• How can pathogens enter the body?

  Through openings like the mouth and nose
• What lines the breathing and digestive systems to protect against pathogens?

  Mucous membranes
• What do mucous membranes secrete to trap microorganisms?

  Mucus
• What role do phagocytes play in the immune response?

  They destroy trapped microorganisms
• What enzyme found in mucus destroys bacteria?

  Lysozyme
• Where else is lysozyme found besides mucus?

  In tears
• What does hydrochloric acid in the stomach do?

  Kills pathogens in food or water
• What are explosive reflexes?

  Responses to expel pathogens
• What are examples of explosive reflexes?

  Sneezing, coughing, vomiting, diarrhea
• How does the body respond to damaged skin?

  It tries to seal the damaged area
• What is the process called that seals damaged skin?

  Blood clotting
• What are the main non-specific defenses of the body against pathogens?

  • Skin as a barrier
  • Mucous membranes
  • Mucus secretion
  • Lysozyme in mucus and tears
  • Hydrochloric acid in stomach
  • Explosive reflexes
  • Blood clotting