Immune system

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

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

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

  Skin
• How does skin help protect against pathogens?

  It acts as a barrier and secretes oils and antimicrobial substances
• What are the two main entry points for pathogens if they cannot get through the skin?

  Nose and mouth
• What adaptations do our noses have to prevent pathogen entry?

  They have hairs and mucus to trap pathogens
• What are the two tubes that pathogens must go through after entering the throat?

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

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

  Cilia
• What happens to the mucus and trapped particles in the respiratory system?

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

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

  About 2
• What happens when pathogens enter the body despite the defenses?

  The immune system takes over to hunt them down
• What is the most important part of the immune system?

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

  Phagocytosis, producing antitoxins, and producing antibodies
• What is phagocytosis?

  A process where white blood cells engulf pathogens
• How do white blood cells produce antitoxins?

  They produce small molecules that counteract toxins
• What are antigens?

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

  Small proteins made by white blood cells that bind to antigens
• How does the immune system remember pathogens?

  It produces antibodies specific to the pathogens for future attacks
• What does it mean to be immune to a disease?

  It means the body can quickly produce antibodies to destroy pathogens
• How does the human body defend against pathogens?

  • Physical and chemical barriers (skin, mucus, cilia)
  • Immune response (white blood cells)
  • Phagocytosis, antitoxin production, antibody production