The gastrointestinal tract develops from the endoderm during the 3rd week of gestation. By the 4th week, the foregut, midgut and hindgut regions form and contribute to different parts of the GI system. Notable milestones in GI development include formation of the stomach, esophagus, liver and pancreas by 5-7 weeks and intestinal growth and peristalsis by 8-23 weeks. Tracheo-esophageal fistula and esophageal atresia are congenital disorders where the esophagus fails to develop properly, often requiring surgical correction. Types I-V describe variations in connections between the esophagus and trachea.