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Gastrointestinal physiology is the branch of human physiology that addresses the physical function of the gastrointestinal (GI) tract.The function of the GI tract is to process ingested food by mechanical and chemical means, extract nutrients and excrete waste products.
[medical citation needed] The rate of digestion is also dependent of the material being digested, as food composition from the same meal may leave the stomach at different rates. [32] Total emptying of the stomach takes around 4–5 hours, and transit through the colon takes 30 to 50 hours. [30] [33] [34]
Transit time through the small intestine is an average of 4 hours. Half of the food residues of a meal have emptied from the small intestine by an average of 5.4 hours after ingestion. Emptying of the small intestine is complete after an average of 8.6 hours. [30]
Both forms of gastrin are found in the gastric antrum and duodenum: Gastrins stimulate the secretion of gastric acid, pepsinogen, intrinsic factor, and secretin; stimulate intestinal mucosal growth; increase gastric and intestinal motility Big gastrin: 3839: 34: Secretin-glucagon family: Secretin: 3056: 27: Duodenum and jejunum
The coordinated contractions of these layers is called peristalsis and propels the food through the tract. Food in the GI tract is called a bolus (ball of food) from the mouth down to the stomach. After the stomach, the food is partially digested and semi-liquid, and is referred to as chyme. In the large intestine the remaining semi-solid ...
Gastrin is a linear peptide hormone produced by G cells of the duodenum and in the pyloric antrum of the stomach.It is secreted into the bloodstream. The encoded polypeptide is preprogastrin, which is cleaved by enzymes in posttranslational modification to produce progastrin (an intermediate, inactive precursor) and then gastrin in various forms, primarily the following three:
Human nutrition deals with the provision of essential nutrients in food that are necessary to support human life and good health. [1] Poor nutrition is a chronic problem often linked to poverty, food security , or a poor understanding of nutritional requirements. [ 2 ]
Dietary fiber (fibre in Commonwealth English) or roughage is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes. [1] Dietary fibers are diverse in chemical composition and can be grouped generally by their solubility , viscosity and fermentability which affect how fibers are processed in the body ...