Complexity in pulmonary arterial tree structure-function

In attempting to understand the complexity of pulmonary arterial tree structure and function relationships, the authors have made morphometric measurements on the lungs of mice, rats, and dogs. The authors constructed a morphometrically based hemodynamic model for which the measured morphometric parameters can be used as inputs to examine the sensitivity of model hemodynamic function to morphometry. The results suggest that, insofar as the model embodies the important structure function relationships in the pulmonary arterial tree, neither shear stress equalization nor minimization of hydraulic plus metabolic work can explain the tree design. Minimization of perfusion heterogeneity may be another selective force contributing to the evolution of the structure