Lungs & Gas Exchange

• Which organ system are the lungs part of?

  Respiratory system
• What are the tiny air sacs in the lungs called?

  Alveoli
• What is the name of the process by which oxygen moves through the wall of the alveoli, into the blood?

  Diffusion
• How are alveoli adapted for efficient gas exchange?

  Their walls are only one cell thick...

  ...which provides a short distance for diffusion

  There are many of them giving a large total surface area 

  They are moist, which allows the gases to dissolve, and therefore diffuse more easily 
• Which gas diffuses from the blood in the capillaries, into the air in the alveoli?

  Carbon dioxide 
• What passes down its concentration gradient from the alveoli, into the bloodstream?

  Oxygen
• Which substance inside red blood cells does oxygen bind to?

  Haemoglobin 
• True or false? Carbon dioxide is transported around the body dissolved in the blood plasma. 

  true
• A boy has a breathing rate of 14 breaths per minute. How many breaths will he take in 30 seconds?

  7