Short Bowel Syndrome: A malabsorption syndrome resulting from extensive operative resection of the SMALL INTESTINE, the absorptive region of the GASTROINTESTINAL TRACT.Irritable Bowel Syndrome: A disorder with chronic or recurrent colonic symptoms without a clearcut etiology. This condition is characterized by chronic or recurrent ABDOMINAL PAIN, bloating, MUCUS in FECES, and an erratic disturbance of DEFECATION.Glucagon-Like Peptide 2: A 33-amino acid peptide derived from the C-terminal of PROGLUCAGON and mainly produced by the INTESTINAL L CELLS. It stimulates intestinal mucosal growth and decreased apoptosis of ENTEROCYTES. GLP-2 enhances gastrointestinal function and plays an important role in nutrient homeostasis.Parenteral Nutrition: The administering of nutrients for assimilation and utilization by a patient who cannot maintain adequate nutrition by enteral feeding alone. Nutrients are administered by a route other than the alimentary canal (e.g., intravenously, subcutaneously).Malabsorption Syndromes: General term for a group of MALNUTRITION syndromes caused by failure of normal INTESTINAL ABSORPTION of nutrients.Intestinal Atresia: Congenital obliteration of the lumen of the intestine, with the ILEUM involved in 50% of the cases and the JEJUNUM and DUODENUM following in frequency. It is the most frequent cause of INTESTINAL OBSTRUCTION in NEWBORNS. (From Stedman, 25th ed)Jejunostomy: Surgical formation of an opening through the ABDOMINAL WALL into the JEJUNUM, usually for enteral hyperalimentation.Colonic Diseases, Functional: Chronic or recurrent colonic disorders without an identifiable structural or biochemical explanation. The widely recognized IRRITABLE BOWEL SYNDROME falls into this category.Intestine, Small: The portion of the GASTROINTESTINAL TRACT between the PYLORUS of the STOMACH and the ILEOCECAL VALVE of the LARGE INTESTINE. It is divisible into three portions: the DUODENUM, the JEJUNUM, and the ILEUM.Digestive System Surgical Procedures: Surgery performed on the digestive system or its parts.Parenteral Nutrition, Home: The at-home administering of nutrients for assimilation and utilization by a patient who cannot maintain adequate nutrition by enteral feeding alone. Nutrients are administered via a route other than the alimentary canal (e.g., intravenously, subcutaneously).Enteral Nutrition: Nutritional support given via the alimentary canal or any route connected to the gastrointestinal system (i.e., the enteral route). This includes oral feeding, sip feeding, and tube feeding using nasogastric, gastrostomy, and jejunostomy tubes.Syndrome: A characteristic symptom complex.Parenteral Nutrition, Total: The delivery of nutrients for assimilation and utilization by a patient whose sole source of nutrients is via solutions administered intravenously, subcutaneously, or by some other non-alimentary route. The basic components of TPN solutions are protein hydrolysates or free amino acid mixtures, monosaccharides, and electrolytes. Components are selected for their ability to reverse catabolism, promote anabolism, and build structural proteins.Digestive System Abnormalities: Congenital structural abnormalities of the DIGESTIVE SYSTEM.Enterocolitis, Necrotizing: ENTEROCOLITIS with extensive ulceration (ULCER) and NECROSIS. It is observed primarily in LOW BIRTH WEIGHT INFANT.Intestinal Diseases: Pathological processes in any segment of the INTESTINE from DUODENUM to RECTUM.Glucagon-Like Peptides: Peptides derived from proglucagon which is also the precursor of pancreatic GLUCAGON. Despite expression of proglucagon in multiple tissues, the major production site of glucagon-like peptides (GLPs) is the INTESTINAL L CELLS. GLPs include glucagon-like peptide 1, glucagon-like peptide 2, and the various truncated forms.Acidosis, Lactic: Acidosis caused by accumulation of lactic acid more rapidly than it can be metabolized. It may occur spontaneously or in association with diseases such as DIABETES MELLITUS; LEUKEMIA; or LIVER FAILURE.Intestinal Absorption: Uptake of substances through the lining of the INTESTINES.Jejunum: The middle portion of the SMALL INTESTINE, between DUODENUM and ILEUM. It represents about 2/5 of the remaining portion of the small intestine below duodenum.Adaptation, Physiological: The non-genetic biological changes of an organism in response to challenges in its ENVIRONMENT.Intestines: The section of the alimentary canal from the STOMACH to the ANAL CANAL. It includes the LARGE INTESTINE and SMALL INTESTINE.Constipation: Infrequent or difficult evacuation of FECES. These symptoms are associated with a variety of causes, including low DIETARY FIBER intake, emotional or nervous disturbances, systemic and structural disorders, drug-induced aggravation, and infections.Enterocytes: Absorptive cells in the lining of the INTESTINAL MUCOSA. They are differentiated EPITHELIAL CELLS with apical MICROVILLI facing the intestinal lumen. Enterocytes are more abundant in the SMALL INTESTINE than in the LARGE INTESTINE. Their microvilli greatly increase the luminal surface area of the cell by 14- to 40 fold.Inflammatory Bowel Diseases: Chronic, non-specific inflammation of the GASTROINTESTINAL TRACT. Etiology may be genetic or environmental. This term includes CROHN DISEASE and ULCERATIVE COLITIS.Intestinal Mucosa: Lining of the INTESTINES, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. In the SMALL INTESTINE, the mucosa is characterized by a series of folds and abundance of absorptive cells (ENTEROCYTES) with MICROVILLI.Abdominal Pain: Sensation of discomfort, distress, or agony in the abdominal region.Ileum: The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Gastrointestinal Agents: Drugs used for their effects on the gastrointestinal system, as to control gastric acidity, regulate gastrointestinal motility and water flow, and improve digestion.