What is the primary product of the glycogen-lactic acid system?

The primary product of the glycogen-lactic acid system is lactic acid. This system is critical during anaerobic respiration, particularly when the body needs energy quickly and oxygen supply is limited, such as during intense exercise.

When glycogen is broken down in muscle cells to produce energy without sufficient oxygen, it is converted into glucose and subsequently metabolized through glycolysis. This process generates ATP, which is the immediate energy currency of the cell. However, under anaerobic conditions, after glycolysis occurs, pyruvate is not fully oxidized in the mitochondria to produce carbon dioxide and water. Instead, it gets converted into lactic acid.

As lactic acid accumulates, it can be transported back to the liver where it can be converted back into glucose in a process known as gluconeogenesis, but during the initial phase of intense activity, lactic acid is the central product indicating that the anaerobic pathway is dominant. Thus, lactic acid is considered the primary end product of the glycogen-lactic acid system.