Ohutsuolta

Ohutsuolta, or the duodenum in English, is the first and shortest section of the small intestine, connecting the stomach to the jejunum. It runs about 25 to 28 centimeters in adults and comprises four parts: the superior (bulb) portion, the descending, horizontal, and ascending portions. The duodenum receives chyme from the stomach through the pyloric sphincter and mixes it with bile and pancreatic secretions via the hepatopancreatic ampulla, which opens at the major duodenal papilla.

The mucosa contains absorptive cells and Brunner's glands in the submucosa that secrete alkaline mucus to neutralize acid. Plicae circulares and villi aid digestion and absorption, including iron, calcium, and folate.

Blood supply comes mainly from the gastroduodenal and superior pancreaticoduodenal arteries, with venous drainage to the portal system. Lymphatics drain to pancreaticoduodenal nodes and then to the celiac and superior mesenteric nodes. Innervation is via the vagus and thoracic splanchnic nerves.

Clinical notes: the duodenum is a common site of peptic ulcers, especially in the first part, and is involved in conditions such as celiac disease and Crohn's disease. Its proper function is essential for digestion and progression of chyme to the jejunum.