immune systems & defences

• 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 prevent pathogen entry?

  Hairs and mucus trap pathogens
• What are the two tubes leading 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 happens to trapped particles in mucus?

  They are moved to the throat
• What does the stomach produce to kill pathogens?

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

  About 2
• 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 is phagocytosis?

  Engulfing pathogens by white blood cells
• 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 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
• What are the key functions of white blood cells?

  • Phagocytosis: engulf pathogens
  • Producing antitoxins: counteract toxins
  • Producing antibodies: target foreign antigens
• How do we know the body's defense system is effective?

  It survives millions of pathogen attacks daily