Function of Duodenum

Duodenum is a short tube which is the first segment of small intestine. It connects the stomach to small intestine and is one of the important parts of digestive system. It performs the function of digestion and absorption. Duodenum is the region where liver, pancreas and gallbladder open to facilitate its function. The following article gives out a description on structure and function of duodenum.

Structure of Duodenum

Duodenum is present below the stomach and is quite close to the pancreas and liver. It is divided into four segments, namely superior, descending, horizontal and ascending duodenum. The inner lining of duodenum is made of crypts that help in increasing the surface area to aid better digestion. Duodenum consists of smooth muscles that help in moving the waste materials down the large intestine.

Function of Duodenum

Duodenum performs a wide range of functions. It helps in:

  • Food digestion
  • Movement of food throughout the digestive tract
  • Controlling gastric emptying rate and regulating hunger
  • Nutrient absorption

Digesting the Food

The main function of duodenum is to receive the incompletely digested food and to digest it completely. The foods are mixed with stomach enzymes and acids in the stomach and digested partially. The mixture of stomach acids and semi digested foods is called chyme. Duodenum receives chyme and starts the process of breaking down it further. It receives pancreatic juices from pancreas, bile juice from gallbladder and liver that helps in further breakdown of food. These secretions are very essential for the digestion process to take place in duodenum.

Regulating Gastric Emptying Rate and Hunger

Duodenum is also responsible for regulating the gastric emptying rate and triggers the hunger signals produced by the stomach. Gastric emptying is the process of food leaving the stomach, also called emptying of stomach. Duodenal epithelium secretes certain hormones that are responsible for the above functions. Pylorus is a small circular opening at the junction of stomach and duodenum. It allows the chyme to enter into duodenum. The epithelial cells of duodenum releases two hormones called cholecystokinin and secretin.

  • Cholecystokinin is secreted in response to presence of amino acids and fats in the food.
  • Secretin is secreted in response presence of excess acids.

These two hormones also stimulate the pancreas, liver and gallbladder to secrete their respective enzymes.


Duodenum absorbs the nutrients from the digested food. The nutrients thus absorbed enter into bloodstream.

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