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   '''C<sub>1</sub> C<sub>2</sub>''' = The concentrations in the two areas   
 
   '''C<sub>1</sub> C<sub>2</sub>''' = The concentrations in the two areas   
 
   '''L''' = distance seperating the two areas
 
   '''L''' = distance seperating the two areas
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Ficks law demonstrates that the rate of diffusion can be maximised by increasing the area over which diffusion can occur, minimising the distance it has to occur over and increasing the gradient it occurs along.  In the body it tends to be the former two which are taken into account when adapting surfaces for diffusion to occur over.
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==Diffusion as a Transport Mechanism==
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Diffusion is very efficent over short distances and does not requrie energy.  As such it is used in a variety of body systems where gradients and membranes suited to allow it are found.  However over large distances diffusion is very slow hence the need for a circulatory system to carry say oxygen around the body.  Although oxygen enters the blood in the lungs and leaves the blood in the tissue by diffusion the circulatory system is needed to fill the gap in between.
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