duodenum

Examples of duodenum in the following topics:

• Digestive System: Small and Large Intestines

  • The human small intestine, over 6 m long, is divided into three parts: the duodenum, the jejunum, and the ileum.
  • The "C-shaped," fixed part of the small intestine, the duodenum, is separated from the stomach by the pyloric sphincter which opens to allow chyme to move from the stomach to the duodenum where it mixes with pancreatic juices.
  • Digestive juices from the pancreas, liver, and gallbladder, as well as from gland cells of the intestinal wall itself, enter the duodenum.
  • It produces bile: a digestive juice that is required for the breakdown of fatty components of the food in the duodenum.
  • When chyme containing fatty acids enters the duodenum, the bile is secreted from the gallbladder into the duodenum.

• Hormonal Responses to Food

  • In the duodenum, digestive secretions from the liver, pancreas, and gallbladder play an important role in digesting chyme during the intestinal phase.
  • In order to neutralize the acidic chyme, a hormone called secretin stimulates the pancreas to produce alkaline bicarbonate solution and deliver it to the duodenum.
  • Not only does CCK stimulate the pancreas to produce the requisite pancreatic juices, it also stimulates the gallbladder to release bile into the duodenum .

• Digestion and Absorption

  • The next step of carbohydrate digestion takes place in the duodenum.
  • The chyme from the stomach enters the duodenum and mixes with the digestive secretions from the pancreas, liver, and gallbladder.
  • In the duodenum, other enzymes – trypsin, elastase, and chymotrypsin – act on the peptides, reducing them to smaller peptides.
  • These enzymes are produced by the pancreas and released into the duodenum where they also act on the chyme.
  • When chyme enters the duodenum, the hormonal responses trigger the release of bile, which is produced in the liver and stored in the gallbladder.