Human Physiology - William F. Ganong 2002

Respiration
Gas transport between the lungs and tissues
Introduction

Partial pressure gradients for O2 and CO2, indicated in the graph (Fig. 35-1), play a crucial role in gas transport and determine the downward flow of O2 from the air through the alveoli and Blood to the Tissues, whereas for CO2, the downward flow is from the tissues to the alveoli. The amount of transported gases may appear grossly inadequate because over 99% of the O2 dissolved in the blood binds to Hemoglobin, an oxygen-carrying protein, and over 94.5% of the CO2 dissolved in the blood undergoes a series of Reversible Chemical Reactions to be converted into Other Compounds. Consequently, the presence of hemoglobin increases the oxygen-carrying capacity of the blood by 70-fold, while reactions involving CO2 increase the blood CO2 content by 17-fold. This chapter examines the mechanisms responsible for The transport of O2 and CO2.



Last update: 10/08/2026

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