The development of cellular polarity in transport epithelia.

From the above discussion, it can be seen that the establishment of epithelial polarity plays a critical role in mammalian development. Functional and structural transitions in the vectorial processes of epithelial tissues in the developing embryo accompany critical events during development. Pathophysiologic states may arise due to either genetic or acquired abnormalities of polarity. Immaturity of vectorial transport functions frequently accompany the onset of premature birth and result in abnormal function of transport epithelia. Further definition of the molecular mechanisms that lead to the establishment and maintenance of epithelial polarity, as well as the developmental sequence of vectorial transport functions in developing epithelia, will lead to better understanding and treatment of fundamental disease states in the fetus and newborn.