What is the action of insulin?

Insulin is the hormone that controls how glucose gets into your cells to give them energy after you eat. If you think of your cells having a lock on them and insulin is the key. Once your food is digested, the glucose goes into the blood stream. However glucose is unable to get into cells on its own. Therefore your pancreas releases insulin which binds to cells and allows them to take on glucose. This allows them to respire and prevents damage to them due to dehydration caused by osmosis if blood glucose levels are too high. Insulin also works on the liver. It makes the liver turn the glucose to glycogen and stores it for times when blood glucose gets low.