Immune System #38

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

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

  • Physical and chemical barriers
  • Immune system
• What acts as a physical barrier to pathogens?

  Skin
• How does skin help protect against pathogens?

  It secretes oils and antimicrobial substances
• Through which openings can pathogens enter the body?

  Nose and mouth
• What adaptations do noses have to trap pathogens?

  Little hairs and mucus
• What are the two tubes that lead from the throat?

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

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

  Cilia
• What is the pH level of stomach contents?

  About 2
• What does the stomach produce to kill pathogens?

  Hydrochloric acid
• What happens when pathogens enter the body despite defenses?

  The immune system hunts them down
• What is the primary type of cell in the immune system?

  White blood cells
• What are the three important functions of white blood cells?

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

  Engulfing pathogens by white blood cells
• What do antitoxins do?

  Counteract toxins produced by pathogens
• 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 antigens and signal for 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
• How does the body defend against pathogens daily?

  • Physical barriers (skin)
  • Chemical barriers (mucus, acid)
  • Immune response (white blood cells)