Vékonybélé

Vékonybélé, in Hungarian referring to the small intestine, is the longest component of the digestive tract, extending from the pyloric region of the stomach to the cecum of the large intestine. In adults, it typically measures about 5 to 7 meters in length and is highly coiled within the abdominal cavity.

It consists of three main sections: the duodenum (nyombél), the jejunum, and the ileum. The duodenum receives chyme from the stomach mixed with bile and pancreatic juice. The jejunum is the principal site of nutrient absorption, followed by the ileum, where bile acids and vitamin B12 are reabsorbed.

The inner surface is folded into villi and microvilli, forming a large absorptive area. The mucosa contains enterocytes, goblet cells, and crypts of Lieberkühn. In the ileum, Peyer’s patches contribute to gut immunity. Digestive enzymes on the brush border aid in the breakdown of carbohydrates and peptides.

Absorption involves carbohydrates, amino acids, lipids, vitamins, and minerals, as well as significant water reabsorption. Blood from the vékonybélé drains via the superior mesenteric vessels into the hepatic portal system.

The small intestine is innervated by the enteric nervous system, with parasympathetic input from the vagus nerve and sympathetic input modulating motility and secretion.

Clinical relevance: disorders include celiac disease (villous atrophy causing malabsorption), Crohn’s disease (often affecting the ileum), infections, and obstructions. Malabsorption and surgical resections can impact nutritional status.