[Sidenote: Glycogen--how formed and where stored]
Glycogen is commonly called animal-starch. It exists in the liver in
small quantities. All carbohydrates are digested in the alimentary canal
and absorbed into the blood in the form of simple sugars of the glucose
group. When these sugars reach the liver they are again built up into
a complex carbohydrate very similar to starch in composition. This
glycogen or animal-starch is stored in the liver until the body has
need of it, when it is changed into glucose and given back to the body
in the form of energy. (See "Metabolism of Carbohydrates," Lesson VI, p.
202).