What processes determine normal function of the lung?
As just indicated, the main function of the lung is the exchange of the gases oxygen and carbon dioxide. So, the blood in the alveolar capillaries takes oxygen from inhaled air that is in the alveoli. Then, the oxygenated blood circulates through the body to deliver the oxygen to the tissues. In the exchange of gases, the blood in the alveolar capillaries releases carbon dioxide to the alveoli. Then, when we breathe out (exhale or expire), the carbon dioxide is removed from the alveoli through the airway and eliminated from body. Accordingly, three processes determine normal lung function: • Ventilation • Diffusion • Blood supply Ventilation is the moving of air into and out of the lung. This process requires an open (unobstructed) airway. Increasing and decreasing the size of the chest cavity is what accomplishes the movement of air. You see, as the chest cavity enlarges, a vacuum is created in the airway and air rushes in. Then, with breathing out, the chest cavity becomes smaller an
