exchanging surfaces

• Common features

  • large surface area
  • high rate of diffusion
  • thin exchange surfaces
• small intestine is adapted for efficient absorption of food into the blood stream.

  • It is lined with lots of of finger-like projections called villi which increases the surface area
• The lungs are responsible for taking in oxygen from the air so it can be carried by the blood to cells that require it for aerobic respiration.

  • They have lots of tiny air sacs called alveoli which allow for efficient gas exchange.