☆1 volatile acid-—H2CO3 metabolism of protein, carbohydrate and fat co+O、HCO3→H+HCo3 CA daily production 300-40QL/d Reabsorption in kidney Excretion: lung RBC、 kidney tubulesepithelium, alveolar pithelial cell, gastric mucosadaily production ：300-400L/d Excretion:lung ❖ 1.volatile acid—— H2CO3 CO2 ＋ H2O H2CO3 CA metabolism of protein, carbohydrate and fat H+ + HCO3 - Reabsorption in kidney RBC、kidney tubulesepithelium 、alveolar epithelial cell 、gastric mucosa