RegenerationRegeneration of HCO-coupled with the bufferingof secreted H+ byfiltered Na,HPOin distal tubulesRenalTubularTubularinterstitialcellslumenfluidNat+NaHPONatNaNatH++NaHPO,HCO3ATPHCOa+H+CI-H2CO3NaH2PO4CarbonicanhydraseH20CO2+CO2
Regeneration Regeneration of HCO3 - coupled with the buffering of secreted H+ by filtered Na2HPO4 in distal tubules ClATP
Regeneration ofHcO,coupled withbuffering of H+ by NH3in proximal tubularcellsGlutamineTubularlumenglutaminaseNH3NH3α-keto glutaric acidNH4TNH2CO3Na+NatH+H+HCO3
Regeneration of HCO3 - coupled with buffering of H+ by NH3 in proximal tubular cells Glutamine Tubular lumen glutaminase NH3 NH3 -keto glutaric acid NH4 + NH4 + H2CO3 Na+ Na+ HCO3 - H+ H+ ATP
Regeneration of HCO coupled with bufferingof H+ by NH, in collecting tubular cellsTubularCollectingRenallumentubularinterstitialcellsfluidNH3NH3NaCFATPK+HCO3-+H+H+H2CO3CI-Carbonic+NH,*+ CanhydraseH20+CO2
Regeneration of HCO3 - coupled with buffering of H+ by NH3 in collecting tubular cells Cl-
Net acid excretion by kidney= NH t excretion + urinary titratable acid-bicarbonate excretion= nonvolatile acid productionIn acidosis, a net addition of HcO3- back toblood as more NH4t and urinary titratableacid are excretedIn alkalosis, titratable acid and NH4texcretion drop to 0, whereas HcO3excretion increases(No new bicarbonate is generated)
Net acid excretion by kidney = NH4 + excretion + urinary titratable acid – bicarbonate excretion = nonvolatile acid production In acidosis, a net addition of HCO3 - back to blood as more NH4 + and urinary titratable acid are excreted In alkalosis, titratable acid and NH4 + excretion drop to 0, whereas HCO3 - excretion increases (No new bicarbonate is generated)
Parameters of acid - basebalance1.pH = 6.1 + Ig HCO3/ H2CO3Normal value of pH in arterial blood7.4±0.05pH normal, may be1) acid-base balance2) compensatory acid-base disorder3) mixed acid-base disorder
Parameters of acid – base balance 1.pH = 6.1 + lg HCO3 - / H2CO3 Normal value of pH in arterial blood 7.4±0.05 pH normal, may be 1) acid-base balance 2) compensatory acid-base disorder 3) mixed acid-base disorder