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Post by Trevor on Jan 23, 2014 9:32:20 GMT
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Post by kickingfrog on Aug 12, 2015 15:59:29 GMT
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Post by kickingfrog on Aug 13, 2015 16:44:29 GMT
Studies of gastrointestinal transit have clearly demonstrated two related phenomena important to understanding this process: Substances do not move uniformly through the digestive system. Materials do not leave segments of the digestive tube in the same order as they arrive. In other words, a meal is typically a mixture of chemically and physically diverse materials, and some substances in this mixture show accelerated transit while others are retarded in their flow downstream. ... it is difficult to state with any precision how long ingesta remains in the stomach, small intestine and large intestine. Nonetheless, there have been many studies on GI transit, and the table below presents rough estimates for transit times in healthy humans following ingestion of a standard meal (i.e. solid, mixed foods). 50% of stomach contents emptied 2.5 to 3 hours Total emptying of the stomach 4 to 5 hours 50% emptying of the small intestine 2.5 to 3 hours Transit through the colon 30 to 40 hours Remember that these are estimates of average transit times, and there is a great deal of variability among individuals and within the same person at different times and after different meals. www.vivo.colostate.edu/hbooks/pathphys/digestion/basics/transit.html
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Post by kickingfrog on Dec 29, 2017 17:06:01 GMT
Digestion is the process of breaking down food into nutritive components that can be absorbed by the bloodstream and delivered to the cells. It begins with the mechanical breakdown of food in the mouth, where smaller food particles then enter the stomach through the esophagus. Chemical digestion through enzymatic action and acidic secretions further hydrolyzes the food in the stomach, which then enters the small intestine after 2 hours. The final breakdown of food occurs in the small intestine. The pancreas and gall bladder discharge digestive juices to hydrolyze carbohydrates, fats and proteins. When the digested food is down to absorptive levels, the nutrients travel down the intestinal walls through the action of peristalsis. This process pertains to the muscular movement that occurs in the digestive tract, where alternating contractions and relaxations generate wave-like motions that push the nutrients forward. The intestinal lining is permeated with tiny, finger-like projections known as microvilli. These microscopic structures greatly increase the surface area of the intestinal walls to take in more nutrients. The blood vessels found in each microvillus absorb the nutrients into the bloodstream to be circulated throughout the body and provide the cells with the energy to perform essential life processes. www.reference.com/science/nutrients-enter-bloodstream-3bba2c8f8a3d5475#
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