ohutsuolessa

ohutsuolessa is the Finnish term for the small intestine, the long, coiled section of the digestive tract between the stomach and the large intestine. It extends from the pyloric sphincter to the ileocecal valve and consists of three regions: the duodenum, the jejunum, and the ileum. The duodenum receives chyme from the stomach mixed with bile and pancreatic juice, where the majority of chemical digestion begins. In the jejunum and ileum, most nutrient absorption occurs through enterocytes covered by microvilli on villi, increasing the surface area for uptake of sugars, amino acids, lipids, vitamins, and minerals. Pancreatic enzymes and brush-border enzymes complete digestion; bile acids facilitate fat emulsification and are largely reabsorbed in the ileum as part of enterohepatic circulation. Lipids are absorbed as fatty acids and monoglycerides and transported as chylomicrons via the lymphatic system.

The small intestine also hosts immune tissue, including gut-associated lymphoid tissue and Peyer's patches, contributing to mucosal immunity. The resident microbiota is present but less dense than in the large intestine, and the rapid turnover of epithelial cells supports barrier function.

Disorders affecting ohutsuolessa can impair digestion and absorption, such as celiac disease, Crohn's disease, and lactose intolerance. Diagnostic approaches include endoscopy with biopsy, imaging, and tests of nutrient status or intestinal permeability. Understanding the function and structure of the small intestine is essential for grasping general nutrition and gastrointestinal health.