Explain how blood glucose concentration is controlled in the body

When high levels of glucose in the blood are detected, insulin is released from beta cells in the islets of Langerhan in the pancreas.Insulin then binds to insulin receptors of cells, which causes an increased rate of glucose absorption into the cell (which reduces the blood glucose concentration).Insulin also binds to receptors in the liver, causing glucose to be converted to glycogen (this is glycogenesis), which also reduces blood glucose levels.
In summary: insulin is released in response to high blood glucose levels and acts to reduce blood glucose concentration by increasing its absorption into cells and converting it to a storage form (glycogen).