Figure 8.

Outcomes from differential growth of tissues. Outcomes of differential growth of tissues shown in Figures 4, 6, and 7 are summarized. A. In the presence of a stiff structure such as a smooth muscle layer (SM), differential growth between the tube and the epithelial sheet (Epi) results in the formation of epithelial folds. B. In the absence of a stiff structure, differential growth between the epithelial sheet (Epi) and the tube which is composed of softer extra cellular matrix or mesenchymal layer (EL) results in the formation of the non-uniform tube or of the sinuous tube. C. In the presence of the membrane (Mem) longitudinally binding to the tube, differential growth between the membrane and the tube results in the formation of the sinuous tube. Even in the case that the tube contains a stiff smooth muscle layer (SM), the membrane can deform the tube.