The pancreas is an organ located below the breastbone, close to the stomach and duodenum. It's principle responsibility is to create digestive enzymes and hormones, one of which is insulin. This article will describe how insulin is created in the pancreas and the other hormones that help to modify the blood sugar levels of the body.

The pancreas is made up of exocrine and endocrine cells. Exocrine cells create the digestive enzymes that are passed into the stomach to help break down food.

Endocrine cells are responsible for creating and secreting insulin and it's counterpart glucagon. These hormones are responsible for controlling the level of glucose in the blood at any one time.

Glucose is effectively the energy that keeps the cells in the body functioning. Without glucose the body would starve. Glucose is absorbed from food via the stomach. The bloodstream passes glucose to all the cells in the body.

Endocrine cells are made up of pancreatic islets or Islets of Langerhans (after Paul Langerhans, who discovered them in 1869). Within the pancreatic islets are many smaller cells. Two of these cells produce the hormones insulin and glucagon.

The beta cells create and secrete insulin.

The alpha cells create and secrete glucagon.

These two hormones are responsible for maintaining the glucose level in blood at a constant rate so that all the cells have the required energy to perform their functions. They tend to work in an on/off relationship. When insulin is being secreted, glucagon is absent and vice versa.

The process starts when someone has eaten food. As the food is digested, glucose is passed into the bloodstream and distributed throughout the body. This glucose is used by the body to function normally but if there is any glucose left over or too much glucose in the bloodstream, the pancreas secretes insulin.

Insulin has the effect of acting on many cells in the body to create glycogen. Glycogen is a form of storage for glucose in cells. It is an emergency reserve of glucose in cellular form should the body need it. The principal cells that insulin works on are the liver, fat and muscle cells. Thus glycogen is stored in these cells. This has the effect of keeping the glucose level in the blood to a constant and normal level.

As the food has been absorbed and energy is used by the cells there will come a time when the blood sugar levels get low. This means the cells could be starved of energy and not work effectively. This might occur when somebody is sleeping or dieting.

When the blood sugar level is low, glucagon is created and secreted. It acts on the same cells that insulin works on, notably the liver, fat and muscle cells but instead of creating glycogen it converts glycogen into glucose. The glucose can then by used by the body's cells to continue functioning via the bloodstream. In this way the blood sugar level can always remain constant whether the body is processing food or not.

The pancreas is responsible for ensuring this delicate process continues seamlessly. It is only when the pancreas starts to malfunction that people become aware of the vital role it plays in providing energy to the body and keeping blood sugar levels normal.