The pancreas is a glandular organ with two vital responsibilities. It produces enzymes necessary to digest carbohydrates, fats and proteins, and it and it produces hormones such as insulin, which helps regulate glucose (blood sugar), the body’s main source of energy.

This oblong gland, measuring about 5 to 6 inches (13 to 15 centimeters) long, is located between the stomach and the spine. It is composed of glandular tissue and a system of ducts, which are tubes that carry the fluids secreted by glands. The main duct is known as the pancreatic duct. It transports fluid from the gland to the duodenum, the upper part of the small intestine.

The pancreas is usually described either by the function of its cells or by its parts. It has two functional components:

• Endocrine cells (also known as the islets of Langerhans or islet cells). “Endo” means within. There are about 100,000 endocrine cells scattered throughout the pancreas. They are responsible for producing and secreting hormones into the bloodstream, including insulin and glucagon. These hormones maintain proper glucose levels within the bloodstream and help the body use that sugar for energy within the cells.
  
  
• Exocrine cells (also known as acinar cells or non-endocrine cells). “Exo” means outward. These cells make up the majority of the pancreas. They produce and transport proteins (known as enzymes) and fluids that assist in digestion and leave the body by way of the digestive system.

The pancreas also can be categorized by its five sections:

• Head. The gland’s widest part.
  
  
• Neck. Located between the gland’s head and body.
  
  
• Body. Found between the neck and tail, this part is located in front of the superior mesenteric arteries and veins, which supply the intestines with blood.
  
  
• Tail. The thin tip, found near the spleen.
  
  
• Uncinate process. This part bends backward and is found underneath the pancreas’ body. The superior mesenteric arteries and veins cross in front of this part.

When food is digested, it is transported through the esophagus and into the stomach. There, digestive juices break down the majority of the food. The food then flows into the duodenum, the first part of the small intestine.

At this point, bile, a greenish-yellow liquid that assists in digesting fats, and pancreatic fluids are introduced. These liquids, along with the food, continue through the small intestine, where glucose travels into the bloodstream, and then through the large intestine and rectum.

The glucose traveling through the bloodstream is allowed to enter body cells because of insulin. Without enough insulin, the body is unable to use glucose for energy. High levels of glucose circulating in the blood (hyperglycemia) can damage nerves, blood vessels and other body systems, causing such complications as diabetic neuropathy and diabetic angiopathy.

The islets of Langerhans are composed of various types of cells, including:

• Alpha cells. Produce the hormone glucagon and release it into the body. This hormone raises blood glucose levels.
  
  
• Beta cells. Produce glucose-lowering insulin, necessary to move glucose from the blood into the cells to be used for energy.
  
  
• Delta cells. Produce the hormone somatostatin and release it into the body. Somatostatin is believed to affect the alpha cells’ production of glucagon and the beta cells’ production of insulin.

The pancreas also produces gastrin, a hormone that triggers the stomach to produce acids needed for digestion.