Abstract

The primary function of the respiratory system is to supply oxygen (O2) and eliminate carbon dioxide (CO2), a task that is accomplished in conjunction with the circulatory system, which transports these gases between the lungs and peripheral tissues. This chapter covers the principles and mechanisms involved in the transport of O2 and CO2 in the blood. In particular, it discusses the passive diffusion of gases across the alveolar blood-gas barrier and related factors, and the physical laws and gas properties; it provides a comparison of gas transfer profiles among O2, CO2, carbon monoxide, and nitrous oxide; it defines the lung diffusion capacity (transfer factor) and its measurement; it describes the function of hemoglobin in the transport of O2, the hemoglobin-oxygen dissociation curve, and the factors that regulate hemoglobin oxygen affinity; and finally, it describes the transport of CO2 in the blood, the role of carbonic anhydrase, and the Haldane effect.