Lung development.

The development of the human lung starts at 4 weeks of gestation with the appearance of the tracheal outgrowth from the foregut and continues into early childhood. Survival at birth is dependent on adequate development and maturation of the lung in utero. Abnormal bronchopulmonary development results in congenital lung malformations, and inadequate development is thought to contribute to bronchopulmonary dysplasia. Complex processes and factors influencing lung development are beginning to be elucidated, and further knowledge will hopefully lead to improved interventions to enhance outcomes in vulnerable or affected infants.