How is the blood sugar concentration maintained in the body?

The main organ controlling blood sugar levels is the pancreas. This is both an exocrine and endocrine gland. The endocrine part of the gland is what helps control blood glucose at a healthy level through the release of two main hormones : Insulin and glucagon.When the blood sugar levels increase beyond the normal range, the pancreas secretes insulin into the blood which allows glucose to move from the blood into cells where its used for respiration, or to move into the liver/muscles to be stored as insoluble glycogen.In the opposite situation, if blood sugar levels were to drop below the normal range the pancreas secretes the hormone glucagon into the blood which triggers the liver to breakdown glycogen stores back into glucose and be released into the blood. This is a process of negative feedback control.