The pancreas is an abdominal organ made of glandular tissue and a system of ducts. It has two major functions:

• Exocrine cells produce enzymes that aid in the digestion of carbohydrates, fats and proteins.
  
  
• Endocrine cells produce hormones that regulate the body’s main energy source, glucose (blood sugar). These hormones include insulin, which lowers glucose levels by moving it into cell, and glucagon, which raises glucose levels in the blood.

The pancreas also produces other hormones, such as gastrin (to regulate acid secretion) and somatostatin (to regulate insulin, glucagon and other hormones). These hormones are produced in clusters of cells spread throughout the pancreas. These clusters, called the islets of Langerhans, are composed of specialized cells known as alpha, beta and delta cells.  

Damage to the beta cells can cause insulin production to slow or stop and result in diabetes. Other conditions that can affect pancreas function include:

• Pancreatitis. Inflammation of the pancreas.
  
  
• Pancreatic cysts. Sacs of fluid that are usually caused by pancreatitis.
  
  
• Pancreatic cancer. A form of cancer that spreads quickly and is rarely found in its early stages.
  
  
• Insulinoma. A tumor of the beta cells, usually noncancerous.
  
  
• Pancreatic insufficiency. Occurs when the pancreas fails to make enough enzymes for proper digestion.

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.

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.

People with type 1 diabetes, LADA and other cases of insulin-depended diabetes get insulin through regular syringe injections or other devices such as an insulin pump or inhaled insulin. Other treatment options may include a pancreas transplant or an islet cell transplant. Scientists are trying to develop an artificial pancreas that can detect glucose levels and deliver the needed amount of insulin.

In addition to diabetes and insulin resistance, there are a variety of diseases and conditions that may affect the pancreas, including:

• Pancreatitis. Inflammation of the pancreas that can be either acute or chronic. It occurs when digestive enzymes activate while still inside the pancreas and start digesting the pancreas itself. This disease increases the risk of developing diabetes. Excess use of alcohol is a major cause of pancreatitis and, according to some studies, may be a risk factor for pancreatic cancer.
  
  
• Pancreatic cancer. A serious form of cancer that spreads quickly and is rarely found in its early stages. Risk factors for pancreatic cancer include diabetes and pancreatitis. Symptoms include jaundice (yellowing of the skin and the whites of the eyes), abdominal pain and unexplained weight loss. Treatment is surgical removal of the tumors, if caught early enough.
  
  
• Insulinoma. A tumor of the beta cells, usually benign (noncancerous). Insulinomas cause the pancreas to make excess insulin (hyperinsulinemia), which can cause hypoglycemia.
  
  
• Cystic fibrosis (CF). A genetic disorder in which the body produces thick mucus that interferes with respiratory function and the exocrine system of the pancreas (involving digestive substances and enzymes). As this mucus blocks the pancreatic ducts, it prevents digestive enzymes from reaching the small intestine, which leads to malnutrition and insufficient digestion. A common complication of CF is cystic fibrosis-related diabetes (CFRD), which has some features of type 1 diabetes and some features of type 2 diabetes.
  
  
• Pancreatic cysts. Sacs of fluid that form in the pancreas and are usually caused by pancreatitis.
  
  
• Pancreatic insufficiency. A condition in which the pancreas fails to make enough enzymes for proper digestion. It is not a disease itself, but a sign of another problem. It can result in malabsorption (ineffective nutrient absorption by the intestines), weight loss and diarrhea.
  
  
• Zollinger-Ellison syndrome. A rare condition in which tumors (known as gastrinomas) form in the pancreas or the duodenum. The gastrinomas secrete the hormone gastrin in large amounts, causing heavy acid production and peptic ulcers.
  
  
• Shwachman-Diamond syndrome. A rare condition characterized by improper functioning of pancreatic cells. This condition, which affects people of all ages, is the second most common cause of pancreatic insufficiency in children. It is sometimes mistaken for CF, the leading cause of pancreatic insufficiency in this population.

Many tests of pancreatic function are available. Among those that a physician may order, depending on the suspected condition:

• Glucose tests to assess endocrine function
  
  
• Autoantibody testing to look for the autoimmune damage seen in type 1 diabetes
  
  
• Other blood tests, such as enzyme testing to assess exocrine function or a C peptide test to assess production of insulin
  
  
• Fecal (stool) tests of enzymes, fats or nitrogen
  
  
• Secretin stimulation test, in which a tube is passed through the nose, down the throat and into the stomach and upper part of the small intestine to assess how the pancreas responds to the hormone secretin during digestion
  
  
• Ultrasound
  
  
• CAT scan (computed axial tomography), an imaging test that involves multiple x-rays
  
  
• An imaging test called endoscopic retrograde cholangiopancreatography (ERCP), in which a tube is passed down the throat into the stomach and upper part of the small intestine
  
  
• A type of MRI called magnetic resonance cholangiopancreatography
  
  
• PET scan (positron-emission tomography), a radionuclide imaging test that may be able to measure the mass of beta cells

Physicians have no easy, direct way to detect pancreatic inflammation, an early sign of type 1 diabetes. Biopsies are rarely performed because taking tissue samples from the pancreas is potentially risky.

Scientists in Boston are developing a technique that uses MRI technology to highlight this inflammation after iron particles injected into blood vessels travel to the pancreas. People with type 1 diabetes are being recruited for clinical trials of the new technology.

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about pancreas function:

1. What purposes does my pancreas serve?
   
   
2. How is my pancreas involved in my diabetes?
   
   
3. Do I have, or am I at risk of, any other pancreatic conditions?
   
   
4. Can my diabetes affect the parts of the pancreas involved in digestion?
   
   
5. If I have type 1 diabetes, could my beta cells still be making insulin?
   
   
6. Does my diabetes increase my risk of pancreatic cancer or other pancreatic conditions?
   
   
7. Are there warning signs if there’s a problem with my pancreas?
   
   
8. Are there any tests of pancreatic function I should undergo? If so, what does the testing involve?
   
   
9. What do my test results show? What condition is my pancreas in?
   
   
10. If treatment is needed, what are my options, and which do you recommend?
    
    
11. What can I do to preserve or improve my pancreas function? Do I need to avoid alcohol?