And essentially we want to basically compare two different conditions. One condition is when we have high blood glucose levels. The other condition is when we have low blood glucose levels. And so let's begin with the high blood glucose levels. So let's suppose we just ate a meal that is rich in carbohydrates and so we break down the carbohydrates into the individual glucose molecules and that means the concentration of glucose in the blood essentially rises. And as it rises that signals the release of insulin hormone molecules.