BIOLOGY/WHAT DOES THE PANCREAS DO?

Biology/What Does the Pancreas Do?

Biology/What Does the Pancreas Do?

Introduction

The pancreas is a small organ in the abdomen that produces and secretes substances to aid digestion, as well as hormones that regulate the balance of blood sugar (glucose) levels. Recently, scientists have begun to characterize the stem cell population in the pancreas, but little is yet understood. Bailey, et al (1993) mention a common disease associated with the pancreas is diabetes mellitus type I (DMI), an autoimmune disorder where a person's immune system attacks and destroys his or her own pancreatic islet cells, which produce and secrete insulin. The pancreas is a pear-shaped organ about 6 in (15 cm) long located in the middle and back portion of the abdomen.

It is connected to the first part of the small intestine, the duodenum, and lies behind the stomach. The pancreas is made up of glandular tissue, or cells that form substances to be secreted outside of the organ. Glandular tissues can be categorized as endocrine (secreting directly into the bloodstream or lymph) or exocrine (secreting into another organ). The pancreas is both an exocrine and an endocrine organ.

Discussion

Pancreatic secretions are categorized as exocrine and endocrine. Exocrine secretions are released into ducts that connect to other organs, while endocrine secretions are hormonal and enter the bloodstream directly. The pancreas secretes the enzymes trypsin and chymotrypsin via ducts into the small intestine to aid in protein digestion, as well as pancreatic amylase for starch breakdown and pancreatic lipase for fat digestion (Bailey, et al, 1993).

In addition, the pancreas secretes important hormones including glucagon and insulin. Glucagon and insulin have counteractive effects on blood sugar—glucagon stimulates the breakdown of sugar stores in the liver, raising blood sugar; in contrast, insulin stimulates cells to take up glucose, thus lowering blood sugar levels. Further hormones released by the pancreas are gastrin, somatostatin, and pancreatic polypeptide which act on additional organs. Therefore, the pancreas and its secretions affect multiple organ systems.

Biology/What Does the Pancreas Do?

The digestive juices produced by the pancreas are secreted into the duodenum via a Y-shaped duct, at the point where the common bile duct from the liver and the pancreatic duct join just before entering the duodenum. In this way, a variety of digestive enzymes (trypsin, chymotrypsin, lipase, and amylase, among others) are delivered into the small intestine to aid in the digestion of proteins, fats, and carbohydrates. The enzymes are delivered in an inactive form called zymogens. The zymogens are activated by the chemical substances in the small intestine. The digestive enzymes carried into the duodenum are representative of the exocrine function of the pancreas, in which specific substances are made to be passed directly into another organ (Bennet, 1995).

The pancreas is unusual among the body's glands in that it also has a very important endocrine function. Small groups of special cells called islet cells throughout the organ make such hormones as insulin and glucagon, which are critical in regulating blood sugar levels; and vasoactive intestinal peptide, which ...