Lung forms as a diverticule from the foregut, followed by branching . Figure 14-10 Endodermal epithelium form trachea, bronchi and bronchioli. Connective tissue around these is of mesodermal origin. Branching branching requires the presence of mesenchyme around the endoderm epithelium. Lamina-free epithelium tips invaginate by microfilament contraction.
New cleft is stabilized by deposition of collagen fibrils by the mesenchyme.
Extra figure digestive system Formation of diverticules from the endodermal tube leads to formation of liver, gallbladder and pancreas. Extra figure provided Participation of surrounding mesenchyme.