Library · Physiology
Where muscle gets its energy
Make it clearer
Muscle moves by spending ATP, the molecule the cell uses as its energy currency. And there is a problem: the ATP the muscle has stored lasts only a few seconds.
So it makes more as it goes, and it does that by three different routes that hand off the baton, like three tanks emptying one after another. The first is phosphocreatine, a molecule stored in the muscle itself that lends its phosphate to rebuild ATP on the spot. The second is anaerobic glycolysis, which breaks down sugar without needing oxygen. The third is aerobic respiration, which does use oxygen.
Each one has its turn and its duration. Phosphocreatine covers around fifteen seconds. Glycolysis holds out for close to a minute of activity.
When the effort is easy or you are at rest, the third one is in charge. Nearly all the ATP then comes from aerobic respiration, which happens inside the mitochondria, the structures in the cell that burn nutrients with oxygen.
In brief
Muscle moves by spending ATP, and its stored supply lasts only a few seconds of contraction.
It is replenished by three routes: phosphocreatine, which hands its phosphate back to ADP; anaerobic glycolysis; and aerobic respiration.
Three tanks that hand off the baton as the one before runs dry.
Phosphocreatine covers about fifteen seconds and glycolysis close to a minute of activity.
At rest or with moderate effort, nearly all ATP comes from mitochondrial aerobic respiration.
Sources (1)
- OpenStax, Rice UniversityAnatomy and Physiology 2e, 10.3 Muscle Fiber Contraction and RelaxationPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated