2014-18 Chemical buffering The homeostatic response to acid load Extracellular buffers Intracelluar buffer: bone Ca** release 1. Chemical buffering by the extracellular and intracellular buffers 2. Changes in alveolar ventilation to control the PCO2 3. Alterations in renal H* excretion to regulate the plasma HCO3- concentration The homeostatic response to acid load Acid production and excretion 1. Chemical buffering by the extracellular and intracellular buffers 2. Changes in alveolar ventilation to control the PCO2 3. Alterations in renal H* excretion to regulate e plasma HCo3- concentration add excretion and endogenous RENAL HYDROGEN EXCRETION Excretion of ht in a intercalated cells (1)reabsorption of the filtered HCO3 Tubular Lumen Collecting tubule P (2 )excretion of the 50 to 100 meg of H+ 2. Excretion of nh4+ in the urine oH+co→3Hco32014-1-8 2 Chemical buffering • Extracellular buffers • Intracelluar buffer: bone, Ca++ release, osteoclast activation The homeostatic response to acid load 1. Chemical buffering by the extracellular and intracellular buffers. 2. Changes in alveolar ventilation to control the PCO2. 3. Alterations in renal H+ excretion to regulate the plasma HCO3- concentration. The homeostatic response to acid load 1. Chemical buffering by the extracellular and intracellular buffers. 2. Changes in alveolar ventilation to control the PCO2. 3. Alterations in renal H+ excretion to regulate the plasma HCO3- concentration. RENAL HYDROGEN EXCRETION (1) reabsorption of the filtered HCO3- (2) excretion of the 50 to 100 meq of H+ produced per day 1. Formation of titratable acid 2. Excretion of NH4+ in the urine Tubular Lumen Collecting tubule Peritubular capillary H+ H2O2 OH- + CO2 3HCO3 - CA H+ Cl￾ATPase ATPase H+ K+ Excretion of H+ in a intercalated cells H+ H+