Gas exchange

• What is the main function of the lungs?

  Gas exchange
• How does blood collect oxygen in the lungs?

  The heart pumps blood to the lungs
• What are the two main tubes that air passes into the lungs through?

  Trachea and bronchi
• What prevents the trachea from collapsing during inhalation?

  Rings of cartilage
• What are the smaller tubes that the trachea splits into called?

  Bronchioles
• What are alveoli?

  Tiny air sacs for gas exchange
• What is the primary function of alveoli?

  Sites of gas exchange
• How does oxygen move from the air into the bloodstream?

  Through diffusion in the alveoli
• What happens to carbon dioxide in the bloodstream?

  It diffuses back into the air
• What adaptations do alveoli have for efficient gas exchange?

  Thin walls, large surface area, good blood supply
• Why is a good blood supply important for alveoli?

  It maintains a steep concentration gradient
• How does breathing affect gas exchange in the lungs?

  It increases the rate of diffusion
• What does breathing bring into the alveoli?

  Fresh oxygen
• What does breathing remove from the alveoli?

  Carbon dioxide
• What are the key adaptations of the lungs for gas exchange?

  • Millions of alveoli for large surface area
  • Very thin walls for short diffusion path
  • Good blood supply to maintain concentration gradient
• Describe the process of gas exchange in the alveoli.

  1. Oxygen diffuses from air into blood
  2. Carbon dioxide diffuses from blood into air
  3. Fresh oxygen is brought in by breathing
  4. Carbon dioxide is removed by breathing