. Electrolytes in biological systems, incorporating papers presented at a symposium at the Marine Biological Laboratory in Woods Hole, Massachusetts, on September 8, 1954 . SECRETORY H ?CI" H -?CO, Hco; >C02+ HjO^^HjCO, I CI" H+ + HCOj HCI Fig. 2. Three models of paired ion exchange across the gastric mucosa which would gen- erate a diffusion potential. Forced ionic movement mediated by a hypothetical carrier X is indicated by heavy lines and net passive diffusion along a concentration gradient is indicated by a broken line, a: Redox anion pump. Two iron carrier molecules are indi
. Electrolytes in biological systems, incorporating papers presented at a symposium at the Marine Biological Laboratory in Woods Hole, Massachusetts, on September 8, 1954 . SECRETORY H ?CI" H -?CO, Hco; >C02+ HjO^^HjCO, I CI" H+ + HCOj HCI Fig. 2. Three models of paired ion exchange across the gastric mucosa which would gen- erate a diffusion potential. Forced ionic movement mediated by a hypothetical carrier X is indicated by heavy lines and net passive diffusion along a concentration gradient is indicated by a broken line, a: Redox anion pump. Two iron carrier molecules are indicated. The ferric form of the carrier transfers Cl~ from the nutrient to the secretory surface. At the secretory surface the carrier is reduced, generating H"*" and liberating Cl~. At the nutrient surface the carrier is oxidized with formation of 0H~, and the carrier takes up Cl~. To generate a mucosal current, some of the H"*", the H^ formed by the lower carrier in the figure, diffuses back to the secretory solution and is neutralized by 0H~, with a net negative charge transfer as- sociated with Cl^. b: Bicarbonate bi-ionic potential. This model is similar to the redox anion pump except for the diffusing ion. Bicarbonate ions, removing some of the 0H~ ions in the nutrient solution, diffuse into the secretory solution. There HCOs^ is neutralized by H"*", and CO2 redistributes by diffusion. The net result is a transfer of a CI" ion and net negative charge from the nutrient to secretory solution, c: Forced anion exchange. In this model there is forced exchange of CI" against HCOs". As in 26, the mucosal current arises from HCO3 diffusion from the nutrient to secretory solution. This HCOs" is continuously recycled. This model would generate H"*" if, in addition to HCOs^ diffusing from the nutrient solution, fur- ther HCO3" was formed in the secretory solution from CO2. This additional HCOs" would be accepted by
Size: 1552px × 3221px
Photo credit: © The Bookworm Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, booksubjectelectrolytes, booksubjectphysiologyc
