How is oxygen and carbon dioxide transported in human beings?

(a) Transport of oxygen: The oxygen in the alveolar air is taken up by blood in the alveolar blood vessels to be transported to all the cells in the body. In human beings, the respiratory pigment, called haemoglobin present in the red blood corpuscles carries oxygen to different tissues of the body.

(b) Transport of carbon dioxide: Carbon dioxide is more soluble in water. Hence is mostly transported from body tissues in the dissolved form in our blood plasma to lungs. Where it diffuses from blood to air in the lungs.