The pyruvic acid is then transformed into lactic acid that accumulates in muscle tissue and body fluids eventually lowering the pH to a level incompatible with cellular function. Work becomes subjectively more strenuous as the accumulation of lactic acid in muscle and blood is associated with the feeling of muscle fatigue. It is released into the serum because of tissue injury and is present in increased concentration in myocardial infarction or acute damage to liver cells. If glycolysis occurs in the absence of oxygen, it is called anaerobic. If it occurs in the presence of oxygen, it is called aerobic.
Glycolysis is a form of catabolic metabolism.
Innumerable control mechanisms are at work in cells and tissues to maintain static or constant conditions in the internal environment. Through these a pathway can be activated as needed or can be inhibited as products accumulate. The body fluid that bathes the body cells is termed the extra-cellular fluid. Cells are automatons that are capable of living, growing, and performing their functions so long as the proper concentrations of oxygen, glucose, the different electrolytes, amino acids, and fatty substances are available. A compound formed in the body in anaerobic metabolism of carbohydrate.