Blood glucose is the quantity of glucose contained in the blood stream of the individual. It's the prime source of energy for muscles, tissues and other body organs. Glucose is present in most food products. The blood is responsible for carrying glucose to different cells of the body. Insulin is necessary for converting glucose in energy. Insulin is a certain hormone which is introduced by the pancreas of the individual.
Usually the blood sugar levels stays in the narrow boundaries; even so the levels are somewhat lower in the early morning and slightly more after the meals.