Most important form of carbon-dioxide transport in the blood

(As bicarbonates) (670- Ganong 22nd) (642- K.S 4th) (612-13- Ganong 23rd)Carbon dioxide is transported in blood in four wavs1. As dissolved CO2 form - 7%2. As carbonic acid - negligible3. As bicarbonates - 63%4. As carbamino compounds - 30%Transport of carbon dioxide as BicarbonatesAbout 63% of CO2 is transput ted as bicarbonate. From plasma, the CO2 enters the RBCs. In the RBCs, CO2 combines with water to form carbonic acid. The reaction inside RBCs is very rapid. The rapid formation of carbonic acid inside the RBCs is due to the presence of an enzyme called carbonic anhydrase. This enzyme accelerates the reaction, carbonic anhydrase is present only inside the RBCs and not in plasma. This is why the carbonic acid formation is at least 200 to 300 times more in the RBCs than in plasmaThe carbonic acid is very unstable. Almost all carbonic acid (99.9%) formed in red- blood corpuscles dissociates into bicarbonates and hydrogen ions. The concentration of bicarbonates ions in the cell increases more and more. The increased concentration of bicarbonate inside the RBC causes diffusion of bicarbonates ions through the cell membrane in to the plasma