Embryo Folding

The embryo folding is a fundamental process that illustrates the differential growth rate and the flexion of the embryo. This phenomenon is orchestrated by the notochord, which plays a crucial role in establishing embryonic polarity and in the structural organization of the ectoderm. Between the eighteenth and twentieth day of development, the notochord influences the formation of the neural plate, leading to a slowdown in the growth of ectodermal cells located directly above it, while lateral cells continue to grow faster. This growth imbalance leads to the formation of the neural groove, essential for the future development of the nervous system.

As the embryo folds around its vascular system, the heart becomes an anchor point, facilitating a flexion movement that is often compared to a fetal position. This growth mechanism is fueled by the fluid mesoderm, while trophic information comes from the endoderm and the mother via the umbilical cord. Cephalization, which accompanies this process, initiates a series of transformations, including cardialization and the formation of the septum transversum, which are essential for the development of internal organs. This complex process highlights the interconnection between different embryonic tissues and their role in morphogenesis.