Simulation of Gas Exchange and Pulmonary Blood Flow Using a Water-Displacement Model Lung
The transport of oxygen by blood to the tissues begins at the lungs. Here fresh inspired oxygen diffuses into the blood while metabolically produced carbon dioxide diffuses out of the blood. To perform this simple function the lungs require a large surface area. This is achieved by the lungs having a complex sponge-like structure, consisting of millions of microscopic gas-exchanging units each with their own blood supply. In the healthy lung these myriads of units can be treated as one large unit. This simplification has allowed the development of numerous mathematical models describing lung ventilation, gas exchange and perfusion. The simpler mathematical models consist of just three compartments: a dead space, Vd (the ventilated but non gas-exchanging airways of the lungs), an alveolar volume, Va (the combined volume of the gas exchange units) and a gas-exchanging blood volume, Qp (pulmonary blood flow). Many of these mathematical models make further simplifications and assume that the ventilation of the lungs is continuous rather than tidal.
KeywordsDead Space Carbon Dioxide Concentration Pulmonary Blood Flow Alveolar Space Alveolar Volume
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