25. Reclamation of HCO 3 - or secretion of H + in proximal tubules CA Na + (filtered) (CA)
26. ATPase + HPO 4 2- H 2 PO 4 - Cl - (filtered) Regeneration of HCO 3 - or secretion of H + in distal tubules and collecting duct Urine acidification Urine pH: 4.5-4.8 ~ 8.0
27.
28.
29. Glutamine NH 3 α -Ketoglutarate acid H 2 CO 3 H + HCO 3 - Na + glutaminase + NH 4 + Na + NH 4 + HCO 3 - H 2 CO 3 H + NH 3 H + CO 2 +H 2 O CA ATPase NH 3 Cl - Proximal tubular cells Distal and collecting tubular cell Tubular lumen Ammonia secretion in proximal tubule and distal and collecting tubule capillary
70. Alkaline tide: net HCO 3 - release into the blood stream during gastric acid secretion Sustaining factor: hypokalemia,hypochloremia and hypovolemia chyme