Chapter 29: Transport of Oxygen and Carbon Dioxide in the Blood

The chapter explores the oxygen-hemoglobin dissociation curve, demonstrating how factors such as pH, carbon dioxide concentration, temperature, and 2,3-bisphosphoglycerate influence oxygen release at the tissue level. Transport of carbon dioxide occurs through three primary pathways: dissolved gas in plasma, binding to hemoglobin as carbaminohemoglobin, and conversion to bicarbonate ions through carbonic acid intermediates catalyzed by carbonic anhydrase. The bicarbonate buffer system is analyzed in detail, illustrating how this mechanism maintains acid-base homeostasis while simultaneously facilitating carbon dioxide transport from tissues to the lungs. The chapter addresses the chloride shift, the movement of chloride ions into red blood cells that compensates for bicarbonate efflux during carbon dioxide transport. Additionally, it examines how ventilation-perfusion matching ensures optimal gas exchange by correlating blood flow with alveolar ventilation. Clinical applications include conditions such as carbon monoxide poisoning, which disrupts hemoglobin function, and altitude-related physiological adaptations involving enhanced oxygen binding and increased hemoglobin production. The integration of transport mechanisms, chemical buffers, and regulatory feedback systems demonstrates how the body achieves efficient gas exchange and maintains the delicate balance required for cellular respiration and metabolic function.