Glycogen

Glycogen is a Somali term for a substance stored by cells in the form of sugar, known in international languages as glycogen. It is a polysaccharide—a complex carbohydrate made up of many linked glucose units joined in chains. These chains are highly branched, which allows glucose to be extracted rapidly from cells when the body needs energy.

Glycogen is found in the tissues of animals and humans, particularly in the liver and muscles. Its role is similar to that of starch in plants: both are how living organisms store energy in the form of sugar that does not deplete quickly.

Chemical Structure

Glucose units are linked by bonds called glycosidic bonds. The main chain is linear, while branches extend outward at fixed points. The high degree of branching means many cells can access and use it at the same time, allowing breakdown and synthesis to occur rapidly.

Function in the Body

When blood sugar rises—for example after eating—the liver and muscles convert glucose into glycogen, a process called glycogenesis. When blood sugar falls or the body is active, glycogen is broken down and glucose is released (glycogenolysis). The liver's glycogen serves to maintain blood sugar throughout the body; muscle glycogen is used primarily by the muscle itself.

Regulation

Storage and breakdown are controlled by hormones, including insulin and glucagon. Insulin promotes glycogen storage; glucagon and adrenaline increase breakdown. Diseases affecting enzymes involved in glycogen metabolism can cause conditions called glycogen storage diseases, leading to abnormal accumulation or inability to use glycogen.