Transport of Gases

Blood is the medium that carries respiratory gases around the body — oxygen from the lungs to the tissues, and carbon dioxide from the tissues back to the lungs. The two gases are carried in different forms and in very different proportions.

Transport of oxygen

• About 97 per cent of the oxygen is carried by the red blood cells (RBCs).
• The remaining 3 per cent travels dissolved in the plasma.

Transport of carbon dioxide

• Nearly 20 to 25 per cent of the carbon dioxide is carried by the red blood cells. …