Duodenum

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The duodenum is the first segment of the small intestine, extending from the pyloric sphincter of the stomach to the jejunum. It can be divided into the superior, descending, horizontal and ascending parts. Only the proximal section of the superior part is intraperitoneal, and thus the most mobile, while the rest of the duodenum is retroperitoneal. Its functions are to dilute and neutralize digestive juices, digest and process chyme passed on from the stomach, receive pancreatic enzymes and bile, as well as absorb various nutrients. The wall of the duodenum consists of three main layers: an inner mucosa with defined circular folds (of Kerckring), an underlying submucosa and a double layered muscular coat.

Take a detailed look at the duodenum and the structures related to it in the video below.

Take a quiz

Now that you have finished the video on the duodenum, test what you’ve learned with the quiz below! Identify the structures in the video with the identification questions, or really get stuck in with our exam questions.

If you want more of a challenge, take this custom quiz on the small intestine! Fine tune it by choosing topics or individual terms that you want to be tested on.

Browse atlas

Explore parts of the duodenum one by one in this atlas gallery.

Now turn your attention to the anatomical relations of the duodenum.

Summary