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Membrane Potential Consequence Due to Potassium Ion Distribution
  • "As more and more K+ ions move out the charge will increase until the separation of charge develops an electrical potential that opposes the concentration gradient causing the outward movement of K+.

  • Then the potential is large enough to prevent any net movement of K+ and the system is at equilibrium.

  • This potential difference is referred to as the K+ equilibrium potential and can be determined by using the Nernst Equation.

  • Inside mammalian cells the K+ concentration is normally 140 mM/L while the K+ concentration in the solution surrounding the cells is only 4 mM/L.

  • The equilibrium potential required to prevent the K+ from leaving the cells is around -90 mV (millivolts) The specific potential depends upon the exact cell type."

  • courtesy of Robert H. Parsons, Ph.D., Rensselaer Polytechnic Institute, used with permission

 

 
 
 
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