Lung pathogenesis. I. Challenging actions and impairment of bronchopulmonary defence mechanisms (a systemic approach)

A systemic approach to challenging factors and impairment of bronchopulmonary defence mechanisms in lung pathogenesis is attempted. Challenging factors and their penetration ways in the lung tissue are emphasized and the importance of airborne agents, of structures carrying respiratory functions and their relationships are pointed out. The bronchopulmonary defence mechanisms (mucociliary apparatus, alveolar macrophages, own defence of alveolar walls, mesenchymovascular defence of the lung) and their physiological limits of reactivity are analysed. The impairment of these mechanisms due mainly to the overelicitation by challenging factors and the outpassing of superposed mechanisms are structurally analysed and the transformation of physiological means of defence into pathogenic mechanisms is pointed out. Their relationships with the dynamics of factor assemblies and the new substrates developed are emphasized in the multifactorial framework of lung pathogenesis.