Day 1 Question: Formation of the Embryonic Pedicle

The formation of the embryonic pedicle is a crucial process in embryonic development, characterized by a differential growth rate. This phenomenon is manifested by a faster growth of the peripheral part of the embryo, which receives various trophic levels, compared to a center whose growth is slowed down. This dynamic generates a movement, described by the metaphor of tearing, which allows the formation of a layer of cells on the edge of the embryo. This central movement is essential for the orientation of the embryonic pedicle, which, initially uniformly distributed, gradually orients towards a central point.

The origin of the embryonic pedicle is intrinsically linked to the transformation of the astrocelle into a cavity, as well as to the growth of the lumen and the development of the external coelom. These elements interact to create a space that favors the convergence of forces necessary for the formation of the pedicle. It is essential to distinguish the embryonic pedicle from the umbilical cord, as the latter forms later when the growth of the amniotic cavity pushes the vitelline vesicle onto the embryonic pedicle, thus establishing a vital connection for embryonic development.