How is oxygen and carbon dioxide transported in the human beings?
At the alveolar surface, the oxygen diffuses out from the alveoli to the capillaries which surround the alveoli. The oxygenated blood is transported from the lungs to the heart which pumps it to the various parts of the body to supply it to various tissues. At the tissue surface, the oxygen from the blood diffuses out into the tissues and carbon dioxide which is at higher concentration in the tissues, diffuses out into the capillaries. The capillaries transport the carbon dioxide rich blood from tissues to the alveoli where carbon dioxide diffuses out into the alveoli and oxygen enters into the capillaries to be transported to the tissues.
