Gaseous exchange system

• effectiveness of exchange surfaces is increased by having

  1. flattened shape of structures
  2. aveoli in respiratory system
  3. the villi in digestive system
• effectiveness of exchange surfaces is increased by having

  1. a large surface area
  2. short distance for diffusion
• the human lungs are adapted to the respiratory system by having a large surface area, a thin wall, and a large air space
• lungs are organs enclosed within the chest or thorax. air needs to be breathed in to be brought into contact with exchange surfaces within the lungs
• lungs are enclosed in the thorax and surrounded by 12 pairs of ribs, the ribs are moved by 2 sets of intercostal muscles
• gaseous exchange occurs between aveoli and blood in capillaries that supply the lungs
• when breathing the diaphram and rib cage move to create a lower air pressure in lungs than that of air on the outside of the body