What is the main form of carbon dioxide transport in the blood?

The main form of carbon dioxide transport in the blood is through the bicarbonate system. When carbon dioxide is produced in the tissues, approximately 70% of it diffuses into the red blood cells and undergoes a chemical reaction with water, catalyzed by the enzyme carbonic anhydrase. This reaction forms carbonic acid, which quickly dissociates into hydrogen ions and bicarbonate ions. The bicarbonate ion is then transported in the plasma to the lungs, where the process is reversed, allowing carbon dioxide to be expelled during exhalation.

This bicarbonate buffering system plays a critical role in maintaining acid-base balance in the body and facilitates the efficient transport of carbon dioxide from the tissues back to the lungs, where it can be removed from the body.