Blood sugar, or Sugar, is the main sugar found in blood. The body gets Sugar from the food we eat. This sugar is an important source of energy and provides nutrients to the body's organs, muscles and nervous system. The absorption, storage and production of Sugar is regulated constantly by complex processes involving the small intestine, liver and pancreas. Sugar enters the bloodstream after a person has eaten carbohydrates. The endocrine system helps keep the bloodstream's Sugar levels in check using the pancreas. This organ produces the hormone insulin, releasing it after a person consumes protein or carbohydrates. The insulin sends excess Sugar in the liver as glycogen.