Fig. 1. Block diagram of the comprehensive cardiorespiratory system with variable extrapulmonary dead space. (A ) The cardiorespiratory system includes body compartments for coronary circulation, brain, peripheral shunt, liver and gut, kidneys, muscle, other lean tissues, and fat. (B ) The respiratory system incorporates a 14-compartment approximation to Weibel's lung model. In this study, the alveolar dead space was set to zero. Each block represents one compartment with diffusive transport and storage, and the arrows between the blocks represent convective transport. WG = Weibel generations; Alv = alveolar; DS = dead space.