Pancreas
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The pancreas is able to secrete both endocrine and exocrine (digestive enzymes and bicarbonate) substances.
- Endocrine cells form clusters of islets known as the islets of Langerhans. Each islet contains several types of cells but the two most common ones are alpha cells, which produce the hormone glucagon and beta cells, which secrete insulin. Both glucagon and insulin regulate blood glucose levels.
- Exocrine cells produce large quantities of an alkaline, enzyme-rich, watery juice in response to hormonal instructions from the duodenum. The hormones secretin and cholecystokinin stimulate these juices, which travel through a network of secretory ducts.
The main pancreatic duct travels the length of the pancreas and joins with the common bile duct at the ampulla of Vater. This large duct carries digestive enzymes and buffers from the pancreas to the duodenum, which is the meeting point for digestion.
Pancreatic enzymes are the most important of all the digestive enzymes. Three types are produced for the three types of food molecules:
- Amylase, which converts carbohydrates, is similar to the salivary amylase
- Lipase, which converts emulsified fats to fatty acids to glycerol
- Proteolytic, which break down proteins into amino acids. There are four proteolytic enzymes:
- trypsin
- chymotrypsin
- carboxypeptidase
- elastase
This page was updated in November 2005.
