The statement that “Pancreas are the overall controller of the blood glucose level” is correct. The islets of Langerhans in the pancreas monitor the level of blood glucose level. The beta cells of islets of Langerhans produce insulin and release it when the blood glucose levels are high. The release of insulin promotes glucose uptake in cells. The liver also takes up glucose and stores it as glycogen. When the blood glucose level declines to normal point, the release of insulin is stopped.
The alpha cells of islets of Langerhans produce glucagon and release it when the blood glucose levels are low. The release of glucagon causes the liver to break glycogen and release it as glucose in blood. When the blood glucose level increases to normal point, the release of glucagon is stopped.
