title: Entropy and the contractile state.
abstract: Entropy production must accompany the utilization of free energy in any cellular process and is a measure of the degree of randomness or molecular disorder within a system. A highly entropized system approaches equilibrium, is incapable of performing work, and never unrandomizes spontaneously. Therefore, chemical reactions are reversible only if the entropy of the system can be reduced through the expenditure of free energy and at the expense of an increase in the entropy of the surroundings. This concept is discussed in terms of energy production and utilization by myocardial cells under normal and diseased states.
mesh_terms: D000818:Animals; D004734:Energy Metabolism; D006321:Heart / Q000502:physiology* / Q000503:physiopathology; D006801:Humans; D008322:Mammals; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism; D013816:Thermodynamics