Preksha Meditation & Human Health: 2.3.1.4 Function of RBCs

Red blood cells play a critical role in the transport of oxygen and carbon dioxide in the body. Exchange of gases in lungs takes place between alveolar air and blood flowing through lung capillaries. Gases move in both directions through the respiratory membrane. Oxygen enters in blood from the alveolar air because the P0₂ (Partial pressure of oxygen) of alveolar air greater than P0₂ of incoming blood. Another way of saying this is that oxygen diffuses 'down' its pressure gradient. Simultaneously, carbon dioxide molecule exit from the blood by diffusing down the carbon dioxide pressure gradient out into the alveolar air. The PCO, (Partial pressure of carbon dioxide) of venous blood is much higher than the PC0₂ of alveolar air and pulmonary blood converts deoxygenated blood to oxygenated blood (Saladin, 2004).