Gas Exchange in the Lungs

• What should you be able to describe by the end of the video?

  How the lungs are adapted for gas exchange
• What role does the heart play in relation to the lungs?

  The heart pumps blood to the lungs for oxygen
• How many lungs do humans have?

  Two lungs
• What is the name of the tube that air passes into the lungs through?

  The trachea
• What is a key feature of the trachea?

  It contains rings of cartilage
• What is the function of the cartilage in the trachea?

  To prevent the trachea from collapsing
• What do the trachea split into?

  Two smaller tubes called bronchi
• What are bronchioles?

  Smaller tubes that branch from bronchi
• What do bronchioles end in?

  Tiny air sacs called alveoli
• What is the primary function of alveoli?

  Sites of gas exchange
• How are alveoli described in terms of size?

  Microscopic
• What happens to oxygen in the alveoli?

  It diffuses into the bloodstream
• What happens to carbon dioxide in the alveoli?

  It diffuses out of the bloodstream
• What adaptations do alveoli have for gas exchange?

  Millions of alveoli create a huge surface area
• Why do alveoli have thin walls?

  To shorten the diffusion path
• How does a good blood supply aid gas exchange in alveoli?

  It rapidly removes oxygen from the blood
• What effect does breathing have on gas exchange?

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

  Fresh oxygen
• What does breathing remove from the alveoli?

  Carbon dioxide
• How does breathing affect concentration gradients?

  It makes them higher for gases
• What are the 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 rapidly remove oxygen
  • Breathing increases diffusion rate by maintaining concentration gradients
• What is the overall process of gas exchange in the lungs?

  1. Oxygen diffuses into the bloodstream
  2. Carbon dioxide diffuses out of the bloodstream
  3. Fresh oxygen is brought in through breathing
  4. Carbon dioxide is removed through breathing