duodenumtól

The duodenum is the first section of the small intestine, immediately following the stomach. It receives partially digested food from the stomach and plays a crucial role in the chemical digestion of chyme. The name "duodenum" comes from the Latin word "duodeni," meaning "twelve," as it is approximately twelve finger-breadths long in an adult.

The duodenum is a C-shaped tube that extends from the pyloric sphincter of the stomach to the duodenojejunal flexure, where it transitions into the jejunum, the second part of the small intestine. Its primary functions include neutralizing stomach acid, mixing chyme with digestive enzymes from the pancreas and bile from the liver, and initiating the absorption of nutrients like iron and calcium.

Within the duodenum, the Brunner's glands secrete alkaline mucus that helps protect the intestinal lining from the acidic chyme. The pancreas delivers digestive enzymes such as amylase, lipase, and proteases, while the liver and gallbladder provide bile, which emulsifies fats, aiding in their digestion and absorption. The duodenum's structure, with its folds, villi, and microvilli, significantly increases its surface area for efficient nutrient absorption. Despite its short length, the duodenum is a critical site for both digestion and the beginning of nutrient uptake.