part_of part of part of develops from liver primordium septum transversum endodermal part of digestive tract embryonic tissue epithelial sac hepatic diverticulum http://upload.wikimedia.org/wikipedia/commons/4/4f/Gray1088.png in mice, the hepatic diverticulum forms by E9 and expands into an obvious liver bud by E10 The caudal part of the septum transversum is invaded by the hepatic diverticulum which divides within it to form the liver and thus gives rise to the ventral mesentery of the foregut. epithelium of foregut-midgut junction digestive tract diverticulum