The process of gas exchange in the body is called respiration. This process has three basic steps that involve pulmonary ventilation, external respiration, and internal respiration. All three steps are functions that involve gas exchanges between the lungs and the atmosphere. For instance, pulmonary ventilation, or breathing involves the inhalation and exhalation of air between our lungs and the atmosphere. External respiration is the exchange of gases across the respiratory membrane between the alveoli and the blood in the pulmonary capillaries. This is where the capillaries gains O2 and loses CO2. And finally, the Internal respiration is the exchange of gases between the blood in the systemic capillaries and tissue cells. During this process, the blood loses O2 and gains CO2. The metabolic reactions consume O2 and give off CO2 during the manufacturing of ATP. (Jenkins, 2010) Air moves into the lungs when the air pressure inside the lungs is less that the air pressure in the atmosphere. Boyle’s law states that, “The difference in pressure caused by changes in lung volume force air into our lungs when we inhale and out when we exhale.” Pg.748 if volume increases, outside pressure must decrease. This process involves the diaphragm muscle which increases, during forceful inhalations expanding the thoracic cavity allowing greater airflow into the lungs. The exchange of oxygen and carbon dioxide between alveolar air and pulmonary blood occurs by passive diffusion. This process is governed by Dalton’s law and Henrys law. According to Jenkins, Partial pressures determine the movement of O2 and carbon dioxide between the atmosphere and lungs, between the lungs and blood and between the blood and body cells. Each gas must diffuse across a permeable membrane from the area of its partial pressure is higher to a much less area of partial pressure, which makes the rate of diffusion faster. External respiration in the lungs converts to deoxygenated blood...
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