Architecture of the Tracheobronchial Tree

The structure of the mammalian tracheobronchial tree fulfills a number of important and occasionally contradictory requirements. The geometry of the complex system of branching airways allows for efficient transport of gas to and from the lung periphery, while occupying a minimum of volume within the neck and thorax. Individual airways are adequately stiff to sustain the high airflows necessary for extremes of exertion but adequately compliant to narrow during coughing and to permit the removal of accumulated mucus and debris. In addition, bronchial architecture is a major determinant of the pattern of deposition of inhaled particles, a function with important implications for health and disease.