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The Pancreas

The pancreas is an elongated, flattened glandular organ with two vital responsibilities. It produces enzymes necessary to digest carbohydrates, fats and proteins, and it produces insulin, a hormone that is essential in the regulation of glucose (blood sugar), the body's main source of energy.

This oblong gland, which measures 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 and enzymes from the gland to the duodenum, the upper part of the small intestine.

Pancreas Function

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, islet cells or beta-islet cells). “Endo” means within. There are about 100,000 endocrine cells scattered throughout the pancreas. The pancreatic hormones produced in the islets of Langerhans are composed of various types of cells, including alpha, beta and delta cells. These are responsible for producing and secreting hormones into the bloodstream, including insulin (produced by beta cells), which lowers glucose levels, and glucagon (produced by alpha cells), which raises glucose levels. These hormones maintain proper glucose levels within the bloodstream and help the body use that sugar for energy within the cells. Delta cells in endocrine tissue secrete somatostatin, a hormone that inhibits the release of insulin and glucagon. The pancreas also produces gastrin, a hormone that stimulates the stomach to produce digestive acid.

  • 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 of carbohydrates, fats, proteins and acids in the duodenum. The enzymes are secreted into ducts joined to the main pancreatic duct that is found along the length of the pancreas. The enzymes then travel down into the area where the pancreatic duct enters the duodenum together with the bile duct within a bulbous structure known as the ampulla of Vater. Finally, the enzymes enter the duodenum and become activated. Exocrine tissue also secretes bicarbonate that neutralizes stomach acid and inhibits the formation of ulcers.

The pancreas can also be categorized by its five sections:
  • Head. The gland’s widest part, it is on the right side of the abdomen and lies in the curve of the duodenum.

  • Neck. A thin section located between the gland’s head and body.

  • Body. The middle part of the pancreas, it is found between the neck and tail. The body is located in front of the superior mesenteric blood arteries and veins, which supply the intestines with blood.

  • Tail. The thin tip, it is found on the left side of the abdomen near the spleen.

  • Uncinate process. This part bends backward and is found underneath the pancreas’ head. 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 (digest) food. The food then flows into the duodenum where digestion continues.

  • At this point, bile, a greenish-yellow liquid produced in the liver that assists in digesting fats and pancreatic fluids is secreted into the small intestine. 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 for a long period of time (years) can damage nerves, blood vessels and other body systems.

Pancreas Role in Diabetes

Normally, the beta cells in the pancreas continually produce a steady amount of insulin (known as baseline, basal or background insulin) that is just enough to move glucose (blood sugar) into cells. Insulin production automatically increases when the body senses higher levels of glucose circulating in the blood, such as just after a meal.

However, damage to the beta cells can interfere with insulin production and cause type 1 diabetes or latent autoimmune diabetes of adulthood (LADA).

The cause of these forms of diabetes is not completely understood. Many scientists believe that the pancreas stops producing insulin because the beta cells are attacked by T-cells. Part of the immune system, T-cells are programmed to defend against possibly harmful elements. They may mistake the body’s beta cells as being dangerous – an autoimmune response. When the beta cells are attacked, the pancreas stops making insulin.

It has generally been held with type 1 diabetes that the pancreas has no more beta cells. However, several recent studies have found that the pancreas of a person with long-standing type 1 diabetes sometimes still has these insulin-secreting cells. Researchers hope to find a way to keep the pancreas from destroying these cells.

The initial disease process of type 2 diabetes does not involve a malfunction of the pancreas. With type 2, the pancreas is usually producing enough insulin, but the body has developed insulin resistance and is unable to use the insulin effectively, resulting in hyperinsulinemia (excess insulin in the blood).

However, after years with type 2 diabetes, the pancreas sometimes slows production of insulin, and regular insulin administration may be needed. Malfunction of the pancreas is not necessarily part of type 2 diabetes but does cause type 1 diabetes and LADA.

Understanding Insulin and How It Works

Insulin is a hormone. The body needs it for the correct use of food and energy. All hormones are made by glands. The gland that makes insulin is the pancreas. People with diabetes don't make enough insulin. Luckily, we have a way to replace the insulin the pancreas can't make.

Insulin is also a protein. It can't be taken by mouth. It would be digested, just like the food you eat. That is why insulin is taken by injection.

How The Body Uses Insulin

We need energy all the time. Sugar is our main source of that energy. Insulin works as a "key player" to allow sugar into the body's cells.

What Happens When You Eat?

  1. Some of the food in the stomach breaks down into sugars — one of these sugars is glucose, the body's main fuel.

  1. Sugar enters the bloodstream, and the level of sugar in your blood begins to rise.

  1. When your body senses an increase in sugar, it sends a signal to your pancreas.

  1. The pancreas makes insulin and sends it into the bloodstream.

  1. Insulin lowers the level of blood sugar by acting as a key to unlock the body's cells and allowing sugar to pass from the bloodstream into the cells.

  2. The level of sugar in the bloodstream falls as the sugar passes into the cells.

What Happens When You Have Diabetes

  • In type 1 diabetes, your body doesn't make enough insulin. In type 2 diabetes, your cells cannot use the insulin your body makes.

  • In both types of diabetes, sugar builds up in your bloodstream because it cannot enter the cells.

  • Without sugar for fuel in the cells, your body lacks energy.

  • Sugar stays in your blood, and you have high blood sugar levels.

Why High Blood Sugar is Bad

High blood sugar occurs when too much sugar builds up in your blood and there's not enough insulin to lower your levels. Over time, high blood sugar can put your body's blood vessels at higher risk for damage. This damage may lead to the eye, nerve, and kidney "complications" commonly associated with diabetes.