Respiratory component function of the lungs C arbonic aci id H2CO3 Approximately 98% normal metabolites are in the form of co CO2+ H2o H2CO3 excess CO, exhaled by the lungsRespiratory Component ➢ function of the lungs ➢ Carbonic acid H2CO3 ➢Approximately 98% normal metabolites are in the form of CO2 CO2 + H2O  H2CO3 ➢ excess CO2 exhaled by the lungs