Gas Exchange in the lungs

• Carbon dioxide pumped back/diffuses out into the air

  1. Carbon dioxide

  2. Pumped back

  3. Diffuses out

  4. Into the air
• The heart


  Pumps blood
• Blood flow to the lungs

  1. Blood pumps to the lungs

  2. Blood collects oxygen
• Oxygen passes into the lungs

  1. Through a tube

  2. Into the lungs
• Air flow through the lungs

  1. Trachea splits into smaller tubes

  2. Bronchi subdivide into smaller tubes

  3. Bronchioles
• Alveoli


  Tiny air sacs in the lungs
• Alveoli


  • Millions of alveoli mean the lungs have a huge surface area
  • Alveoli have very thin walls so diffusion path is short
  • Alveoli have a very good blood supply