Glycogenolysis is the biochemical process through which glycogen, a stored form of glucose, is broken down into glucose molecules. This process primarily occurs in the liver and muscle tissues, where glycogen is stored. When the body needs energy, such as during exercise or fasting, glycogenolysis is activated to release glucose into the bloodstream, providing a quick source of energy. The process is regulated by hormones, particularly glucagon and epinephrine, which signal the body to initiate glycogen breakdown. Enzymes like glycogen phosphorylase play a crucial role in this process, ensuring that glucose is released efficiently to meet the body's energy demands.