Potassium is a charged mineral, known as an electrolyte, that is especially important for electrical functioning of cells. The more electrically active the cells, the more they will be affected by imbalances of potassium. As such, nerves and muscles are particularly sensitive. While the source of potassium comes from outside the body, the function of the body determines how much is actually available to be used.
Oral and Intravenous Administration
Potassium is taken into the body through oral and intravenous routes. Oral intake is typically from dietary sources, although potassium supplements or medications are also available for those in need of extra potassium. These supplements should not be taken without the guidance of a physician, however. Many foods, such as bananas, contain potassium. Intravenous potassium is sometimes given when the gastrointestinal tract is not working or the potassium is very low. It must be given very slowly, however, to prevent complications.
Intestine
The intestine serves as the gatekeeper for potassium entering the bloodstream. It is the first organ responsible for raising potassium in the body when it is ingested orally. The intestine contains special proteins that absorb the potassium into the cells of the intestine and subsequently extrude it into the bloodstream.
Kidneys
The kidneys are responsible for maintaining potassium in the body. It is a source of potassium because blood filtered to become urine contains potassium, and the kidneys can re-absorb it back into the bloodstream. If they are working properly, the kidneys will reabsorb potassium if the level of potassium is low, or let it be expelled in the urine if the levels are too high.
Cells
The final source of potassium is the inside of the cells. The concentration of potassium inside of cells is much higher than in the blood. In certain circumstances, potassium is released from the cells and out into the bloodstream. For example, traumatic injury to the tissues, such as a crush injury to the muscles, breaks open cells, causing their potassium to spill into the blood. Increased acid in the blood can also raise the potassium. Acids release a positively charged hydrogen, or proton, which enters the cell and displaces potassium.
References
- "Nutrition Concepts and Controversies"; Frances Sizer, et al.; 11th Ed 2007
- "Robbins and Cotran Pathologic Basis of Disease"; Vinay Kumar, et al.; 8th Ed 2009
- "Physiology"; Linda S.Costanzo; 4th Ed 2008
