RT Book, Section A1 Rawtani, Nina A1 Ved, Sudha A2 Freeman, Brian S. A2 Berger, Jeffrey S. SR Print(0) ID 1135742165 T1 Neonatal Respiratory Physiology T2 Anesthesiology Core Review: Part Two Advanced Exam YR 2016 FD 2016 PB McGraw-Hill Education PP New York, NY SN 9781259641770 LK accessanesthesiology.mhmedical.com/content.aspx?aid=1135742165 RD 2024/04/19 AB Lung development is separated into several phases starting at the embryonic stage. This state begins several weeks into conception and is the formation of the lung bud and initial branches of the airways. The lung is a foregut derivative and is recognizable at 25 days of conception as the laryngotracheal groove. If this groove fails to close, it can lead to tracheoesophageal fistulas. The lung divides into the five primordial divisions (two on the left, three on the right) during this stage.