Differentiation of the Mesenchymal Tissues of the Pulmonary and Esophageal Regions.

Section through the pulmonary region, showing the primary bronchi surrounded by vascularized mesenchymal tissue and mesothelium (pleura). The pulmonary mesenchyme still abuts against that of the alimentary canal. At stage 14 the coelomic epithelium has virtually ceased proliferating and the mesenchyme is arranging itself into zones. Angioblasts are forming a net that outlines the esophagus.

Detail from Fig 15-6, O'Rahilly & Müller, 1987, Developmental Stages in Human Embryos.

The drawing by James F. Didusch was made from section 21-4-1 of embryo 6502. Click on the links to view the region of the section shown in the figure or to overlay the drawing on the section. The section is also shown in Fig. 5 ( Fig. 14-7E, O'Rahilly & Müller, 1987)