descending duodenum
Quick Summary
The descending duodenum is the second of four segments of the duodenum, which is the first part of the small intestine. It receives partially digested food from the stomach and begins nutrient absorption.1
The descending duodenum is about 9 to 11 inches long and is roughly horseshoe-shaped. Glands in its wall release hormones that stimulate the pancreas. Ducts from the pancreas and gallbladder enter the descending duodenum at the major duodenal papilla, delivering bicarbonate to neutralize stomach acid, enzymes for digestion, and bile salts to break down fats. The mucous lining of this segment also starts absorbing nutrients like iron and calcium. Inflammation of the duodenum, known as duodenitis, is often caused by the bacterium Helicobacter pylori.1
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