Carbon dioxide is transported in the blood from the tissue to the lungs in three ways:1 (i) dissolved in solution; (ii) buffered with water as carbonic acid; (iii) bound to proteins, particularly haemoglobin. Approximately 75% of carbon dioxide is transport in the red blood cell and 25% in the plasma.
Most carbon dioxide in the blood is transported in the form of bicarbonate ions.
Most carbon dioxide (about 70%) is transported as bicarbonate ions in the plasma. An increase in carbon dioxide in the blood will cause a slight increase in H+ concentration (drop in pH).
How is most carbon dioxide transported from tissues to the lungs? As bicarbonate ions (HCO3−). Carbon dioxide is transported to the lungs mainly as bicarbonate ions in the blood.