Diffusion is the mechanism by which material is transported through other material.
From the biological point of view atomic diffusion plays an important role, being responsible for: perfusion of respiratory in live tissue; passive absorption of certain ions through the plasmatic membrane; intracellular, extracellular and tissue osmatic regulation; water adsorption through roots and freeing vapor all along the respiration process; extrapallial fluid composition responsible for shell and pearl construction; propagation of electric signals in the nervous system by depolarizing the neuron membranes; diverse mechanisms for cellular communication; water and nutrient absorption through the intestinal walls during digestion; in the formation of edemas; etc.
Curiously, diffusion theory was proposed by a physiologist (Fick). However its theoretical development was in Thermodynamics in the XIX century and later had great importance in Material Science in the XX century, of special importance with the development of microprocessing computers.
