What is the Phosphagen System?

Discovery Health

Every muscle cell has some amount of ATP. Adenosine triphosphate (ATP) is the way your body uses biochemicals to store and use energy. There is enough ATP in the cell that the muscle can use immediately, but only enough to last for about three seconds. The muscle must replenish the ATP levels quickly, using a high-energy phosphate compound called creatine phosphate.

An enzyme called creatine kinase removes the phosphate group from creatine phosphate and transfers it to ADP to form ATP. The cell then turns ATP into ADP, and then the phosphagen turns the ADP back into ATP. The muscle continues to work, and the creatine phosphate levels begin to decrease. The ATP levels and creatine phosphate levels working together are called the phosphagen system. This phosphagen system supplies the energy needs of working muscle, but only for 8 to 10 seconds.

Energy is also produced by the Clycogen-Lactic Acid System and aerobic respiration.

Continue Learning about Functions of Muscles

Functions of Muscles

Functions of Muscles

Muscles keep your body moving by contracting and relaxing. In some cases, this movement is voluntary. You use your skeletal muscles to bend your arms or legs when you want. Smooth muscles, however, are part of the involuntary move...

ment within your body. These muscles surround organs of the digestive tract as well as the arteries. You don't have to be aware of the process -- your brain controls the function! One of the most vital muscles is the cardiac muscle, or heart. Understanding the functions of muscles can help you keep them healthy or treat injury as needed.

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.