Potassium is an essential mineral that supports the most basic functions of life, including water balance, nervous system function and control of heartbeat. So important is hormonal control of potassium that an individual would perish within days of depletion of the necessary hormones. Potassium works with other nutrients such as sodium, magnesium and calcium to ensure healthy body function. In addition to hormones, some health conditions may also influence potassium concentration.
Function of Potassium
Potassium is an electrolyte, which means it conducts electricity when dissolved in water. Nerve impulses involve electrochemical activity. Potassium and sodium regulate the body's ability to send nerve impulses, thus controlling all activity of the body. Most of the potassium in the body is contained within cells. A small portion exists outside cells in the fluid surrounding them. The body maintains a strict concentration of electrolytes for which it devotes 20 to 40 percent of your resting energy expenditure. Potassium is also required by some enzymes for essential chemical reactions to occur, including carbohydrate metabolism.
Hormonal Control
Two hormones -- aldosterone and insulin -- control potassium concentration, with the former playing the larger role. Aldosterone is produced by the adrenal glands located on top of the kidneys. When potassium levels rise, aldosterone is released to restore normal levels by increasing potassium excretion in urine. Likewise, when levels drop, less aldosterone is secreted by the adrenal glands and less potassium is excreted. Insulin increases the permeability of cell membranes to take up potassium.
Aldosterone Control
In addition to potassium concentration, other mechanisms exist within the body to regulate aldosterone concentration and, in turn, potassium. If your blood pressure drops, your body will initiate a complex change of chemical reactions involving the kidneys and enzyme secretion. Enzyme activity will then produce other chemicals that will stimulate aldosterone release. Its release will decrease potassium levels while increasing sodium and water retention to raise your blood pressure.
Abnormal Potassium Levels
Other factors can have an influence on potassium concentration in the body. Individuals taking certain types of diuretics, or "water pills," may deplete potassium. This condition, which is known as hypokalemia, can cause bloating, abdominal pain or muscle paralysis. Excess potassium concentrations can occur due to cellular damage from injury or severe burns. Like hypokalemia, excess potassium, or hyperkalemia, can cause similar symptoms, including abnormal heart rhythm. If you have risk factors such as alcoholism or severe vomiting, consult your doctor regarding medical invention for maintaining safe potassium levels.
References
- "Principles of Anatomy and Physiology"; G. Tortora, et al.; 2005
- Linus Pauling Institute; Potassium; Victoria J. Drake; December 2010
- Linus Pauling Institute; Colorado State University Extension; R. Bowen; August 1, 2009
- MayoClinic.com; Low Potassium (Hypokalemia); August 21, 2009
- University of Maryland Medical Center; Hyperkalemia; February 4, 2010
