The lung has a vital function in gas exchange between the blood and the external
atmosphere. It also has a critical role in the immune defense against external pathogens and
environmental factors. While the lung is classified as a relatively quiescent organ with little
homeostatic turnover, it shows robust regenerative capacity in response to injury, mediated
by the resident stem/progenitor cells. During regeneration, regionally distinct epithelial cell
populations with specific functions are generated from several different types of …