[Structure, function and pathophysiology of mucociliary transport system]

There has been growing appreciation of the significant role played by the mucociliary transport system in the body. The mucociliary transport system is an important defense mechanism by which the human body usually maintains its "homeostasis" by protecting the body against invading particles, including bacteria. This system includes two major functional mechanisms; i.e., ciliary transport and mucous secretional systems, each of which is usually complimentary and cooperative. Three hereditary disorders, primary ciliary dyskinesia (immotile-cilia syndrome), cystic fibrosis and Young's syndrome, have been shown to be systemically associated with mucociliary transport failure, leading to male infertility and chronic sinopulmonary infections. Localized mucociliary transport failure, however, is observed in respiratory diseases, especially chronic sinusitis, chronic bronchitis, bronchiectasis and bronchial asthma. We aim, in this review, to draw together those developments in the study of ciliary transport and mucous secretion, the interactions between them and their pathophysiology that can provide a better understanding of the mucociliary transport system of the human body.