ABSTRACT
This chapter presents a ‘‘snapshot’’ of the human lung when it is developed to the point at which survival is just possible-about 25-27 weeks postconception. Our comments will focus on selected events of lung development that seem most likely to make the premature human lung vulnerable to injury during its precocious adaptation to the extrauterine environment. A prior review of this subject by Frank (1) and many of the discussions in other books (2) remain valuable. We will not address important nonlung components of respiration, including development of the thorax and abdomen, development of respiratory control centers, peripheral chemoreceptors, muscles of respiration and their innervation, and reflexes such as the diving and cough reflexes. We focus our review on information relevant to the late canalicular and early saccular stages of normal human lung development. Our comments are greatly amplified by other chapters in this volume and those authors also include important information about abnormal lung development after premature birth.
