Oxygen is transported in the blood by hemoglobin, a protein found in red blood cells. Hemoglobin binds to oxygen in the lungs and releases it in the tissues. The amount of oxygen that can be transported by the blood depends on the concentration of hemoglobin and the partial pressure of oxygen in the blood.

Carbon Dioxide Transport

Carbon dioxide is transported in the blood in three forms:

* Dissolved in plasma

* Bound to hemoglobin

* Carbaminohemoglobin

The majority of carbon dioxide is transported in the blood as bicarbonate ions (HCO3-). Bicarbonate ions are formed when carbon dioxide reacts with water in the presence of the enzyme carbonic anhydrase. Carbonic anhydrase is found in red blood cells and the endothelium of blood vessels.

Hemoglobin also binds to carbon dioxide, but it does so less efficiently than it binds to oxygen. Carbaminohemoglobin is a compound formed when carbon dioxide reacts with the amino acid side chains of hemoglobin.

The transport of carbon dioxide in the blood is important for maintaining the body's acid-base balance. Carbon dioxide is a waste product of cellular respiration, and it must be removed from the body to prevent acidosis.