Specialised exchange surfaces

• Things specialised exchange surfaces have usually have:

  • Large surface area
  • Thin membrane
  • An efficient blood supply (in animals)
  • Ventilation (in gas exchange in animals)
  • Good supply of the external medium
  • Surfaces are permable
• Exchange surface - a part of an organism over which substances are exchanged with the environment
• Leaves - exchange gas

  • flat shape
• Gills -gas exchange

  • lots of gill filament
  • lamellae have lots of capillaries
  • lamellae have thin layer of cells
• Small intestine - absorption of food molecules form gut to blood

  • single layer of surface cells
  • covered in villi
  • capillary network
• Alveoli - gas exchange

  • millions of aveoli
  • air moves in and out
  • thin walls
  • capillary network
• Transport systems - transport the substances to the parts of the body that need them
• Exchange systems - get substance in and out of the bodies of organisms