I. regulation of acid-base balance 1. origin of acid and base in the body volatile acid: H2CO3 (15mol/day) sulfuric acid 1) acids phosphoric acid fixed acid: uric acid (90mmol/L) mesostate 2)base: salt of organic acid; NH3I. regulation of acid-base balance 1. origin of acid and base in the body volatile acid: H2CO3 (15mol/day) sulfuric acid 1) acids phosphoric acid fixed acid: uric acid (90mmol/L) mesostate 2) base: salt of organic acid; NH3