21. The endoderm is amongst the three germ layers that make up the developing embryo. 22. In mice, this structure is known as the Anterior Visceral Endoderm ( AVE ). 23. In triploblastic organisms, the three germ layers are called endoderm , ectoderm, and mesoderm. 24. In the absence of Nanog, mouse embryonic stem cells differentiate into visceral / parietal endoderm . 25. In mice, Chordin is expressed in the node but not in the anterior visceral endoderm . 26. These " Symbiodinium " occur within vacuoles in host cells derived from the endoderm . 27. During development, definitive endoderm and ectoderm differentiates into several gastrointestinal epithelial lineages, including endocrine cells. 28. The tube is lined by endoderm from which the epithelial lining of the respiratory tract is developed. 29. These three " germ layers " are known as the ectoderm, mesoderm, and endoderm . 30. The mesoderm forms at the same time as the other two germ layers, the ectoderm and endoderm .
