Change the Sodium Concentration

The Sodium ion plays a major role in the depolarization of an action potential. The ionic concentration of Sodium determines the magnitude of the action potential and how quickly it occurs. Sodium's extracellular concentration has more affect than its intracellular because the intracellular concentration is so small. Increasing the extracellular concentration of Na+ causes the nerve action potential to have a higher peak and to occur faster. The higher extracellular concentration leads to a larger concentration gradient between the inside and outside of the cell. Therefore, the Sodium can move into the cell more easily. This Sodium influx contributes to the higher peak. Lowering the extracellular concentration of Na+ will have the inverse effect. Now run the model with higher Na_extracellular concentrations and see what happens!!!!

Ionic Concentrations

Na_extracellular 140 (mM) 440 (mM) 
Na_intracellular = 30 (mM)

K_extracellular =3 (mM)

K_intracellular =90 (mM)