Another way of saying this is that absorption of water is absolutely dependent on absorption of solutes, particularly sodium:. As sodium is rapidly pumped out of the cell, it achieves very high concentration in the narrow space between enterocytes. A potent osmotic gradient is thus formed across apical cell membranes and their connecting junctional complexes that osmotically drives movement of water across the epithelium. Water is thus absorbed into the intercellular space by diffusion down an osmotic gradient.
We discuss the absorption of water and different electrolytes separately below. In all cases, the luminal membrane resorption is powered by a NaK ATPase on the basolateral enterocyte membrane. Duodenum and Jejunum: Luminal resorption occurs on a variety of Na-Nutrient symporters, which include monosaccharides, as described in Carbohydrate Digestion and Absorption , as well as amino acids, dipeptides, and tripeptides, as described in Protein Digestion and Absorption.
These mechanisms of sodium resorption are constitutively active and are not physiologically regulated. Water Absorption Water is always absorbed in the alimentary tract through passive osmosis via a mostly paracellular route between enterocyte tight junctions.
Consequently, water absorption is primarily actuated by active absorption of osmotic electrolytes, especially sodium. In cases where a high concentration of unabsorbable solutes remain in the GI lumen, water cannot be resorbed and thus causes an osmotic diarrhea. Chloride Resorption Absorption of Cl - largely occurs through passive diffusion via a paracellualr route. The majority of chloride is resorbed in the small intestine, especially the duodenum and jejunum.
Effects of electrolytes in carbohydrate beverages on gastric emptying and secretion. Osmolality does not affect the gastric emptying rate of oral rehydration solutions. J Parenter Enteral Nutr. Faster gastric emptying for glucose-polymer and fructose solutions than for glucose. The effect of osmolality and carbohydrate content on the rate of gastric emptying.
Accumulation in the blood of a deuterium tracer added to hot and cold beverages. Scand J Med Sci Sports. Effect of meal temperature on gastric emptying of liquids in man. Gastric emptying of cold beverages in humans: effects of transportable carbohydrates. The influence of carbonated water on gastric emptying. New Eng J Med. Effects of carbonated and noncarbonated beverages at specific intervals during treadmill running in the heat.
Consumption of carbonated and noncarbonated sports drinks during prolonged treadmill exercise in the heat. Int J Sports Nutr. Effect of carbonated water on gastric emptying and intragastric meal distribution. Dig Dis Sci. The effects of a carbonated carbohydrate drink on gastric emptying, gastrointestinal distress, and exercise performance.
Rehydration and gastro-intestinal functions. Montrouge, France : John Libby Eurotext ; : 87 — Murray R. The effects of consuming carbohydrate-electrolyte beverages on gastric emptying and fluid absorption during and following exercise. Sports Med. Gastric emptying during prolonged cycling exercise in the heat.
Gastric emptying during exercise: effects of heat stress and hypohydration. Effects of dehydration on gastric emptying and gastrointestinal distress while running. Shi X Gisolfi CV. Fluid and carbohydrate replacement during intermittent exercise. Gastric emptying of a carbohydrate-electrolyte drink during a soccer match. The effect of intermittent high-intensity running exercise on the rate of gastric emptying in man. Sladen GEG. A review of water and electrolyte transport.
Transport Across the Intestine. London, UK : Churchill Livingstone ; : 14 — Dawson IS. A review of fat transport. London, UK : Churchill Livingston ; : — Guandalini S. Intestinal ion and nutrient transport in health and infectious diarrheal diseases. Crane RK. Intestinal absorption of carbohydrate and protein in man.
In: Crane RK , ed. Molecular aspects of sugar:ion co-transport. Ann Rev Biochem. Murer H Burckhardt G. Membrane transport of anions across the epithelia of mammalian small intestine and kidney proximal tubule.
Rev Physiol Biochem Pharmacol. Jodal M Lundgren O. Countercurrent mechanisms in the mammalian gastrointestinal tract. Villous tissue osmolality and intestinal transport of water and electrolytes.
Acta Physiol Scand. Absorption of water and solute from sucrose-electrolyte solutions containing calcium and magnesium. The effects of exercise on intestinal absorption in humans. Water and electrolyte transport during maintenance of isotonicity in human jejunum and ileum. J Lab Clin Med. Absorption from different intestinal segments during exercise. Permeability characteristics of the human small intestine. J Clin Invest. Agre P. The aquaporin water channels. Proc Am Thorac Soc.
Cloning of a new aquaporin AQP10 abundantly expressed in duodenum and jejunum. Biochem Biophys Res Comm. Cloning and identification of a new member of water channel AQP10 as an aquaglyceroporin.
Biochima et Biophysica Acta. The glucose transporter family: structure, function and tissue-specific expression. Biochem J. Structural basis for physiological regulation of paracellular pathways. J Membr Biol.
The mechanisms of sodium absorption in the human small intestine. Contribution of solvent drag through intercellular junctions to absorption of nutrients by the small intestine. Simultaneous determination of gastric emptying and intestinal absorption during cycle exercise.
Modigliani R Bernier JJ. Absorption of glucose, sodium and water by the human jejunum studied by intestinal perfusion with a proximal occluding balloon and at variable flow rates. Glucose absorption from maltotriose and glucose oligomers in the human jejunum. Clin Sci. Further studies on the perfusion method for measuring intestinal absorption in man: the effects of the proximal occlusive balloon and a mixing segment.
The effect of osmolality on absorption from carbohydrate-electrolyte solutions CES in the human jejunal perfusion model. Intestinal absorption of sucrose in man: interrelation of hydrolysis and monosaccharide product absorption. Fructose transport mechanisms in humans. Wheeler K Banwell JG. Intestinal water and electrolyte flux of glucose-polymer electrolyte solutions. Grim E. Water and electrolyte flux rates in the duodenum, jejunum, ileum and colon and effects of osmolarity. Am J Dig Dis.
Changes in blood, plasma and red cell volume after ingestion of hypotonic and hypertonic solutions. Wapnir R Lifshitz F. Osmolality and solute concentration—their relationship with oral rehydration solution effectiveness: an experimental model. Pediatric Res. Dominant role for osmolality in the efficacy of glucose and glycine-containing oral rehydration solutions: studies in a rate model of secretory diarrhoea.
Acta Paediatr. Effect of beverage osmolality on intestinal fluid absorption during exercise. Intestinal fluid absorption during exercise: role of sport drink osmolality and [Na].
Curran PF. Ion transport in the intestine and its coupling to other transport processes. Mechanism of bicarbonate absorption and its relationship between sodium transport in the human jejunum.
Water and solute absorption from hypotonic glucose-electrolyte solutions in human jejunum. Passive movement of water and sodium across the small intestinal mucosa. Effect of sodium concentration in a carbohydrate-electrolyte solution on intestinal absorption.
The role if intraluminal sodium in glucose absorption in vivo. Effect of bicarbonate or base precursor on water and solute absorption from a glucose-electrolyte solution in the human jejunum. Cell-specific effects of luminal acid, bicarbonate, cAMP and carbachol on transporter trafficking in the intestine. Jejunal water transport in man: effects of bicarbonate or tartrate. Fordtran JS Saltin B. Gastric emptying and intestinal absorption during prolonged severe exercise.
Effects of hypohydration on gastric emptying and intestinal absorption during exercise. Effects of exercise intensity on absorption of ingested fluids. Exp Physiol. The kinetics of water absorption in the human intestine. Accumulation of deuterium oxide D 2 O in body fluids following ingestion of D 2 O-labelled beverages. Unilateral fluid absorption and effects on peak power after ingestion of commercially available hypotonic, isotonic and hypertonic sports drinks.
Human intestinal water absorption: direct vs indirect measurements. Gastric emptying, absorption, and carbohydrate oxidation during prolonged exercise. Edelman IS. Exchange of water between blood and tissues. Pinson EA. Water exchange and barriers as studied by the use of hydrogen isotopes. Physiol Rev. Plasma deuterium accumulation following ingestion of different carbohydrate beverages.
Appl Phys Nutr Metabol. Fluid availability of sports drinks differing in carbohydrate type and concentration. Total body water measurement in humans with 18 O and 2 H labeled water. Am J Clin Nutr ; 33 : — The use of deuterium tracer technique to follow the fate of fluids ingested by human subjects: effects of drink volume and tracer concentration and content.
Halliday D Miller AG. Precise measurement of total body water using trace quantities of deuterium oxide. Biomed Mass Spectrom. Comparison of water absorption from an ingested glucose electrolyte solution GES and potable water using a tracer technique in healthy volunteers. Effect of carbohydrate and sodium content on fluid delivery. Nutr Metab. The effect of carbohydrate type, sodium and osmolality on unidirectional water uptake from ingested solutions in man.
Effects of repeated ingestion of high and low glucose-electrolyte solutions and blood 2 H 2 O concentration after an overnight fast. Br J Nutr. Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide.
Sign In or Create an Account. Sign In. Advanced Search. Search Menu. Article Navigation. Close mobile search navigation Article Navigation. Volume Article Contents Abstract. Fate of ingested fluids: factors affecting gastric emptying and intestinal absorption of beverages in humans. Leiper John B. Oxford Academic. Cite Cite John B.
Select Format Select format. Permissions Icon Permissions. Abstract The volume of fluid ingested for rehydration is essential in determining the restoration of euhydration because it must be in excess of the water lost since the individual was last euhydrated.
Table 1 Summary of the factors that affect the rate of gastric emptying of ingested beverages. Open in new tab. Figure 1. Open in new tab Download slide. Figure 2. Table 2 Summary of the factors that affect the rate of intestinal absorption of water from ingested beverages.
0コメント