Final answer:
During the fed state, glycogenesis helps lower blood glucose levels by storing excess glucose as glycogen. In the fasting state, glycogenolysis releases glucose from glycogen to raise blood glucose levels. During exercise, glycogenolysis provides glucose as a fuel source for active muscles.
Step-by-step explanation:
In the fed state (high insulin), glycogenesis is the process by which excess glucose is converted into glycogen and stored in the liver and muscles. This helps to lower blood glucose levels and maintain them within a normal range.
In the fasting state (high glucagon), glycogenolysis is the process by which glycogen is broken down into glucose. This releases glucose into the bloodstream, raising blood glucose levels and providing a source of fuel for the body.
During exercise (high epinephrine), glycogenolysis is also stimulated to release glucose from liver glycogen. In addition, epinephrine stimulates glycogenolysis in muscle, providing glucose as a fuel source for active muscles.