Protective mechanisms of lungs

Respiratory system maintains a close contact with the environment and is constantly exposed to numerous pathogenic factors. In response to action of pathogen, different strategies of specific and non-specific defense have been formed: barrier functions of the epithelium, defense reflexes (coughing, sneezing), muco-ciliary clearance, resident and recruited cells, secretion of a number of proteins and peptides with protective functions. Aim. To systematize modern concepts of the protective mechanisms of lungs on the basis of the data of the relevant literature. In the work, the mechanisms and clinical significance of muco-ciliary clearance, resident alveolar and recruited macrophages, epithelial cells, neutrophils, lymphocytes and platelets are analyzed. Conclusion. The presented mechanisms can counteract the action of various pathogenic agents with sufficient effectiveness. However, in some cases an organism develops insufficient, excessive or perverted response to permeation of pathogens. This results in damage to the lung tissue by exogenous agents and/or by self immune system. Knowledge of protective mechanisms realized in the respiratory system, is necessary for understanding pathogenesis of respiratory diseases and for choice of the optimal treatment tactics.