Why is potassium needed for muscle contraction?

... as potassium chloride. Potassium, along with sodium and calcium, functions as an electrolyte, which means that it balances the amount of fluid in the body and transmits the tiny electrical nerve impulses. Its role in transmitting electrical impulses gives potassium an important role in muscle contractions. read more

Most of the potassium resides inside each cell membrane, while sodium ions remain in the fluid surrounding the cells. The balance between sodium and potassium creates an electrical and chemical gradient that functions to transport molecules in and out of the cell and transmit nerve signals that induce muscle contraction. read more

To repolarize the membrane, after a certain amount of time, potassium channels open up allowing potassium to flow out repolarizing the membrane. Ionic homeostasis is then re-obtained by pumps which pump sodium out and potassium in. read more

In addition, potassium is needed for the contraction of the heart. Potassium levels in the blood should be kept nearly constant or within a narrow range for the proper pumping action of the heart. The heart may stop beating if we have high or low levels of potassium in the blood. We need potassium for stronger muscles. Most of the potassium in the body is found inside the muscle cells. read more