Development of the caudal part of the human embryo

No comprehensive model of the development of the gut and cloaca of human embryos is presently available. This thesis illustrates the normal development of this region in human embryos and foetuses in the form of interactive 3D models. The thesis first describes the changes in the shape and the fate of the hindgut and cloaca. It then continues with the autonomic innervation of these distal parts of the gut. The innervation of organs in embryos is more easily accessible for study than later in life, because nervous tissue is relatively large at that stage. The thesis presents informative models of human embryos and their developing gut and autonomic nerves, but also contains quantitative data on the distribution of areas with more or with less than average growth. Insight into this so-called differential growth among structures in the embryo helps to explain how these structures grow and acquire their definitive shape. The well-defined models of the embryos and their composing parts provide testable models of human development. We are convinced that these short biographies of key organs in the body will help physicians to understand their anatomy and imagine their function and pathology