(a) Far more oxygen is released from oxyhaemoglobin in a more active tissue than in a less active one.
(b) Oxygenation of blood promotes the release of carbondioxide from blood in the lungs.
Carbonic anhydrase is most efficient enzyme. 70% of CO2 produced in R.B.C. combines with water in the presence of carbonic anhydrase to form carbonic acid (H2CO3) which splits to form H+ and HCO3'. CO2 as HCO3' dissociates in the presence of carbonic anhydrase to form H2O and CO2. CO2 passes from blood into air and is passed out along with expired air.
The carbonic anhydrase carries out the following reaction: