What is the process of diffusion and its importance in living organisms?

Diffusion is the movement of particles from an area of high concentration to an area of low concentration. This occurs naturally in environments without outside variables, or can also occur when particles pass through a semi-permeable membrane.

Diffusion happens in many situations in living organisms, and in some instances is a vital process which ensures the healthy development of cells.

Examples of diffusion in living organisms

• The movement of oxygen particles into cells, tissues and organs throughout the human body
  
• The movement of digested food particles from the gut cavity into the capillaries of the small intestine
  
• Release of sodium from the kidneys into the bloodstream.
  

Diffusion also occurs in plants during photosynthesis, when carbon dioxide particles diffuse in

to the plant through the leaf, and oxygen particles, along with water vapour, diffuse out: a process known as transpiration.