Vaccines

• What is the primary function of the human body's defense system?

  To protect against pathogens
• What are the two main components of the human body's defense system?

  • Physical and chemical barriers
  • Immune system
• What role does skin play in the body's defense system?

  It acts as a physical barrier against pathogens
• What substances does skin secrete to kill pathogens?

  Oils and antimicrobial substances
• Through which openings can pathogens enter the body?

  Nose and mouth
• How do noses help prevent pathogen entry?

  By trapping pathogens with hairs and mucus
• What are the two tubes that lead from the throat?

  Trachea and esophagus
• What is the function of mucus in the trachea?

  To trap particles and pathogens
• What structures help move mucus in the respiratory system?

  Cilia
• What happens to trapped mucus in the throat?

  It is swallowed down to the stomach
• What strong acid does the stomach produce?

  Hydrochloric acid
• What is the pH level of stomach contents?

  About 2
• What does hydrochloric acid do to pathogens?

  It kills most of them
• What are the three important functions of white blood cells?

  1. Phagocytosis (engulfing pathogens)
  2. Producing antitoxins
  3. Producing antibodies
• What is phagocytosis?

  Engulfing and destroying pathogens
• What do white blood cells produce to counteract toxins?

  Antitoxins
• What are antigens?

  Foreign substances detected by the immune system
• What are antibodies?

  Proteins made by white blood cells
• How do antibodies function in the immune response?

  They bind to foreign antigens and signal destruction
• What happens when the immune system recognizes a pathogen?

  It produces many specific antibodies quickly
• What does it mean to be immune to a disease?

  The body can quickly destroy pathogens upon re-exposure
• How does the human body defend against pathogens?

  • Physical barriers (skin)
  • Chemical barriers (acids, antimicrobial substances)
  • Immune response (white blood cells)