Exchanging Surfaces

• multicellular cells require exchanging surfaces
• multicellular cells have a small surface area
• exchanging surfaces are adapted to have

  • thin membrane
  • large surface area
• gas exchange

  • occurs in lungs
  • transfers O2 into blood and gets rid of CO2
  • alveoli - large surface area, thin wall, good blood supply
• leaves

  • flattened shape - increases area
  • underneath of leave is stomata which is exchange surface
• villi

  • in small intestine
  • increase surface area
  • digested food to absorb more
  • single layer of surface cells
  • good blood supply
• gills

  • exchange surface in fish
  • thin plates called gill filaments
  • gill filaments have large surface area covered in lamellae