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 the circulatory system?

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

  It increases the rate of gas exchange
• Why do alveoli have very thin walls?


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


  It ensures a steep concentration gradient
• How does breathing affect 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 maintain concentration gradient
  • Breathing increases diffusion rate