The provided source distinguishes between glycogenolysis in the liver and muscle, highlighting their differing metabolic outcomes. Liver glycogenolysis is unique because the liver possesses glucose-6-phosphatase, an enzyme that allows it to convert glucose-6-phosphate into free glucose, which can then be released into the bloodstream. Conversely, muscle glycogenolysis only yields glucose-6-phosphate, which is utilized internally for energy production through glycolysis as muscle tissue lacks glucose-6-phosphatase. This difference explains why the liver can contribute to maintaining blood glucose levels, while muscle energy is for its own use. The source emphasizes the liver's distinct role in glucose homeostasis due to this enzymatic presence.