gas exchange

• What is the primary function of the lungs?

  Exchange of gases
• What prevents the trachea from collapsing during inhalation?

  Cartilage rings
• Where does gas exchange occur in the lungs?

  In the alveoli
• What happens to oxygen and carbon dioxide during gas exchange?

  Oxygen diffuses in, carbon dioxide diffuses out
• What are the adaptations of alveoli for gas exchange?

  • Millions of alveoli increase surface area
  • Thin walls shorten diffusion path
  • Good blood supply enhances gas exchange
• Why is it important for oxygen to be removed rapidly from the blood?

  To maintain a steep concentration gradient
• How does breathing affect the rate of diffusion in the lungs?

  It increases the rate of diffusion
• What does bringing fresh oxygen into the alveoli do to the concentration gradient?

  It increases the concentration gradient
• What is the effect of an increased concentration gradient on the rate of diffusion?

  It increases the rate of diffusion
• What percentage increase in the rate of diffusion is mentioned?

  455%