The distribution of sodium in the body differs from that of potassium. Sodium is the predominant extracellular ion. Renal function is the single most important homeostatic mechanism in relation to plasma concentrations of sodium and potassium. | The distribution of sodium in the body differs from that of potassium. Sodium is the predominant extracellular ion. Renal function is the single most important homeostatic mechanism in relation to plasma concentrations of sodium and potassium. |