Ficks Law Extra

• Diffusion and gas exchange:

  • Gas exchange takes place in alveoli sac across the alveolar membrane
  • a boundary between the external environment and interior of the body
  • Gases cross the respiratory membrane by diffusion
  • In accordance with Fick’s Law
• Fick’s Law:

  • The rate of transfer of a gas through a sheet of tissue is proportional to:
  • tissue area
  • difference in gas partial pressure between the 2 sides
  • diffusion constant
  • inversely proportional to tissue thickness
• Diffusion across alveolar membrane:

  • In accordance with Fick’s law diffusion is dependent on
  • Concentration / pressure gradient
  • Gas solubility
  • Thickness of alveolar membrane
  • Surface area of alveolar membrane
  • Ventilation / perfusion coupling