Duodenum under the Microscope

The duodenum is the first section of the small intestine in humans and most vertebrates, including mammals, reptiles, and birds. In mammals the duodenum is thought to be the main location for iron absorption.

Illustration courtesy Olek Remesz

The duodenum precedes the jejunum and ileum and is the shortest part of the small intestine, where most chemical digestion takes place. In humans, the duodenum is a hollow jointed tube about 10–15 inches (25–38cm) long connecting the stomach to the jejunum.

 Cross section of duodenum captured at 100x magnification with the MW4-HD2 digital microscope.