diffusion

• Diffusion is the spreading out of particles resulting in a net movement from an area of high concentration to an area of low concentration
• Rates of diffusion can be increased by :

  • increasing surface area
  • increasing concentration gradient
  • increasing temperature
  • decreasing distance particles need to travel
• examples of diffusion

  • oxygen and carbon dioxide during gas exchange
  • urea diffuses out and into the blood plasma so it can be excreted in kidneys