Immune System

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

  To protect against pathogens
• How can the defense system be categorized?

  Into physical and chemical barriers, and immune system
• What acts as a physical barrier in the human body?

  Skin
• What substances does the skin secrete to kill pathogens?

  Oils and antimicrobial substances
• How do pathogens typically enter the body?

  Through holes like the nose or mouth
• What adaptations do noses have to trap pathogens?

  Little hairs and mucus
• What are the two tubes leaving the throat?

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

  To trap particles and pathogens
• What structures line the trachea to prevent mucus buildup?

  Cilia
• What happens to trapped particles in the mucus?

  They are moved to the back of the throat
• What strong acid does the stomach produce?

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

  About 2
• What happens to most pathogens in the stomach?

  They are killed by the acid
• What takes over when pathogens enter the body?

  The immune system
• What is the primary function of white blood cells?

  To patrol the body and destroy pathogens
• What is phagocytosis?

  A process where white blood cells engulf pathogens
• What do white blood cells produce to counteract toxins?

  Antitoxins
• What are antigens?

  Substances detected as foreign by the immune system
• What do antibodies do?

  They bind to foreign antigens and signal for destruction
• How does the immune system remember pathogens?

  By producing and storing specific antibodies
• What does it mean to be immune to a disease?

  The body can quickly destroy pathogens upon re-exposure
• What are the key components of the human body's defense system?

  • Physical barriers (e.g., skin)
  • Chemical barriers (e.g., stomach acid)
  • Immune system (e.g., white blood cells)
• What are the functions of white blood cells?

  1. Phagocytosis: Engulf pathogens
  2. Produce antitoxins: Counteract toxins
  3. Produce antibodies: Target foreign antigens
• How does the immune response work?

  • Detection of pathogens by antigens
  • Production of specific antibodies
  • Memory for faster response in future infections