Structure and Function of the Pancreas in Dogs

What Is the Pancreas?

The pancreas is a gland located in the abdominal cavity that serves important functions related to digestion and the production of certain hormones.

Where Is the Pancreas Located?

The pancreas is located within the upper abdominal cavity in close proximity to the stomach, liver and small bowel. The pancreas is composed of two parts or lobes. The right lobe is located near the descending part of the duodenum, which is the first segment of the small bowel (intestine). The left lobe of the pancreas lies next to the stomach.

What Is the General Structure of the Pancreas?

The canine pancreas is composed of right and left lobes, with a small central portion that joins the lobes. Microscopically, the pancreas consists of cells arranged into small sections or lobules. These cells produce a number of digestive enzymes, and they store them within small granules or packets located within the cell.

Two excretory ducts – the accessory duct and the pancreatic duct – carry these enzymes into the intestine where they function in digestion. The anatomic arrangement of these ducts differs slightly between dogs and cats and among individual animals.

The pancreas also contains unique cells (beta cells) that form the islets of Langerhans, which produce insulin. Insulin allows many cells in the body to use blood sugar (glucose); therefore, it is an important hormone in regulating levels of glucose in the blood. The pancreas also produces the hormone, glucagon.

What Are the Functions of the Pancreas?

The pancreas serves two main functions. First, it produces and stores digestive enzymes and fluids. Pancreatic juice is secreted (released) into the intestinal tract in response to eating food. Pancreatic juice contains enzymes needed to digest proteins, carbohydrates, and especially fats.

Secondly, the pancreas produces and secretes hormones vital to the regulation of blood sugar. When the beta cells of the pancreas detect an increase in the blood sugar concentration, insulin is released directly into the blood where it acts to carry glucose into the body's cells. The higher the blood sugar, the more insulin is secreted. Thus, insulin lowers the blood glucose concentration. The hormone, glucagon, acts to increase blood sugar and is released when blood sugar is low.

What Are the Common Diseases of the Pancreas?

There are a number of common diseases of the pancreas.

Pancreatitis. One of the most important, and potentially dangerous, diseases is inflammation of the pancreas. Pancreatitis is a common disease of dogs, and often arises when foods high in fat content are eaten. It usually causes loss of appetite, vomiting, abdominal pain and depression. In severe cases, the condition can be fatal.

Diabetes mellitus. Another serious disease of the pancreas is diabetes mellitus or sugar diabetes. This common disorder of dogs represents an underproduction or excessively low secretion of insulin. Inadequate production of insulin causes the blood sugar to become too high. Although the circulating level of glucose is high in the blood, many cells cannot use it for energy, and serious side effects develop.

Pancreatic cysts and abscesses. These are less common diseases of the pancreas. Pancreatic abscesses are small pockets of infection that may develop as a complication of pancreatitis.

Exocrine pancreatic insufficiency. A unique condition called EPI represents a deficiency in digestive pancreatic enzymes and leads to an inability to digest food properly. This disease occurs much more often in dogs than in cats and affects German shepherd dogs more than other breeds.

Pancreatic carcinoma. Cancers occur infrequently but are very serious conditions. A cancer of the glandular portion of the pancreas is called pancreatic adenocarcinoma, and it is a highly invasive cancer. Unique pancreatic cancers of the hormonal components of the pancreas develop only rarely in the cat. Insulinoma is a tumor that produces insulin, glucagonomas secrete glucagon, and gastrinomas produce excessive amounts of gastrin hormone.

What Types of Diagnostic Tests Are Used to Evaluate the Pancreas?

Commonly used tests in evaluation of the pancreas include the following:

Abdominal radiographs (x-rays)

Abdominal ultrasound

Lipase and amylase levels in the blood

Trypsin-like immunoreactivity (TLI), a blood test that assesses production of digestive enzymes

Blood sugar, especially in patients with diabetes

Measurements of glucose and ketones in the urine

Measurement of insulin levels in the blood

Measurement of vitamins and folate levels in the blood