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How does glycogen provide stored energy in the liver and muscles?

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Tall, dense stalks of sugarcane grow on both sides of a narrow path, with green leaves arching overhead and sunlight illuminating the plants. — sugar Lines of sugarcane before harvest.

Glycogen serves as a vital energy reservoir in animals, stored primarily in the liver and muscle cells. It is a highly branched polysaccharide composed of glucose units that can be rapidly mobilized when energy is required.12

The process of breaking down glycogen into glucose is known as glycogenolysis. This process is stimulated by hormones such as glucagon and epinephrine when blood glucose levels fall or during the fight-or-flight response.3

In the liver: Glycogenolysis converts stored glycogen into free glucose, which is then released into the bloodstream to maintain normal blood glucose levels for the entire body.3
In the muscles: Glycogen is broken down into glucose-6-phosphate, which enters glycolysis directly within the muscle cells to produce adenosine triphosphate (ATP), providing the immediate energy needed for muscular activity.3

This dynamic system ensures that animals have an accessible carbohydrate reserve to meet fluctuating metabolic demands.2