Insulin is a hormone secreted by the beta cells of the pancreas. Another hormone, glucagon is secreted from the alpha cells of the same organ. These hormones act in opposition to each other. When you eat a meal the blood glucose concentration rises, the pancreas senses this rise and secretes insulin to lower the blood glucose(blood sugar). This is called a negative feedback system because it attempts to return the body to a state of homeostasis.
Glucagon causes the blood glucose level to rise raising your blood sugar. This happens when the body senses the blood sugar level is too low. The liver is primarily responsible for this rise in blood glucose concentrations. This process is also a homeostatic mechanism the body uses to return the blood sugar levels to normal.
Insulin is a hormone secreted by pancreas that regulates the body's use of sugar and other food ingredients including protein, fat, and mineral products, such as potassium and phosphate.
Pancreas increases the secretion of insulin into the blood when food is absorbed into the bloodstream, speeding up the movement of nutrients from the bloodstream into target cells located mainly in liver, muscle, and fat tissues. Glucose and other simple sugars are used for immediate energy or converted to glycogen for storage. Amino acids move into cells and there form the building blocks for proteins. Fatty acids, produced by the digestion of fats, are converted to tryglycerides for storage and later used for energy.
Certain insulin-related abnormalities cause the disease called diabetes, in which the body is unable to use sugars properly and glucose this increases their levels in the blood. Diabetes may be caused by different reasons such as insufficient production of insulin in the body, or inability of the body to utilize insulin properly.
Diabetes is treated by giving the patient additional amount of insulin, which is usually injected under the skin, as insulin taken by mouth, gets destroyed by digestive. This treatment does not cure diabetes, but only controls the disease and allow the patient to live an almost normal life.