Diversity and importance of tracheobronchial glands in mammalian species.

Abstract This article focuses on tracheal submucosal glands and their role in health and disease. The occurrence, distribution and morphology of tracheobronchial glands differ among vertebrate – and even mammalian – species. Tracheal glands are of major importance in physiology but also in pathological conditions such as tracheobronchitis, acute and chronic lung injury, cystic fibrosis and others. Some species do not possess tracheal glands; tracheobronchial clearance is performed by other secretory units.