What makes a good lung? The morphometric basis of lung function

The functional capacity of the human lung as gas exchanger is to a large extent determined by structural design. Quantitative structure-function correlations can be established by morphometry. A very large surface of air-blood contact, together with a very thin tissue barrier, are required to per-mit adequate oxygen uptake under work condi-tions. However, these design features also pose problems, such as how to ventilate and perfuse this large surface evenly and efficiently, or how to ensure mechanical stability against surface forces with a minimum of supporting tissue. The discus-sion focuses on the extent to which novel design principles are used to overcome such problems by designing the airways as a fractal tree and th