jelito

Jelito, in Polish medical terminology, refers to the small intestine, the section of the digestive tract between the stomach and the large intestine. In adults it measures about 5–7 meters in length and has a diameter of roughly 2–4 cm. It consists of three sections: the duodenum, the jejunum, and the ileum. Its primary role is the chemical digestion and most of the absorption of nutrients.

The lining of the jelito features villi and microvilli that greatly expand the surface area, enabling efficient absorption. Digestive secretions from the pancreas and bile mix with chyme in the duodenum, allowing enzymatic breakdown of carbohydrates, proteins, and fats. The jejunum is the main site of nutrient absorption, while the ileum absorbs bile acids, vitamin B12, and other nutrients. Transit time through the small intestine generally ranges from about two to six hours.

The small intestine participates in immune defense through gut-associated lymphoid tissue, including Peyer's patches, and hosts a resident microbiota that shapes digestion and immunity. Abnormal bacterial growth or motility can contribute to conditions such as small intestinal bacterial overgrowth (SIBO).

Clinical relevance: disorders affecting the jelito include celiac disease, Crohn's disease, malabsorption syndromes, and short bowel syndrome after extensive resection. Diagnosis relies on endoscopy, imaging, and tests of absorption; treatment focuses on managing the underlying condition, dietary adjustments, and nutritional support.