Insulin controls the sugar levels of the body. In some diabetic patients, insulin hormone level is not normal. Hence, insulin injection is given to such patients to compensate for the reduced insulin hormone secretion. Such cases of diabetes are called Insulin Dependent Diabetes Mellitus (IDDM). such as closure of eyes on exposure to flash of light and salivation in the mouth at the good smell of food. In spinal reflexes, it acts as a collection centre of information without any direct involvement in reflex action.