ABSTRACT
Potassium is the most common cation in the body. Adults typically have between 3 and 4 moles of potassium, 98% of which is located intracellularly Potassium’s clinical importance comes chiefly from the fact that the ratio of intracellular to extracellular potassium is the primary determinant of the resting membrane potential (Em). Increased extracellular potassium decreases the I:E ratio and reduces the resting membrane potential; decreased extracellular potassium increases the ratio and hyperpolarizes the membrane (makes Em more negative). Alterations in the Em disrupt depolarizing tissues, e.g. neural, cardiac, and muscular.
