The Role of Potassium

Abstract

Potassium is one of the main blood minerals, or electrolytes, essential to both cellular and electrical function. Potassium is the primary positive ion, or cation, found in the cells, where more than 90% of the total body stores of potassium is contained. Along with sodium, potassium regulates the water balance and the acid-base balance in the blood and tissues, and plays a critical role in the transmission of electrical impulses in the heart. The active transport of potassium into and out of the cells is crucial to cardiovascular and nerve function. When potassium enters the cell, it instigates a sodium-potassium exchange across the cell membrane. In the nerve cells, this generates the electrical potential that allows the conduction of nerve impulses. When potassium leaves the cell, it restores repolarization to the cell, which allows the nerve impulse to progress. This electrical potential gradient helps generate muscle contractions and regulates the heartbeat. Normal serum potassium levels are between 3.6 and 5.0 mmol/L. If the level of total body potassium declines by just 1% (35 mmol), a serious imbalance in the intracellular and extracellular potassium results. This imbalance alters the electrophysiologic properties of the cell membrane and causes detrimental effects on impulse generation and conduction throughout the heart [1].