What is gastrulation in embryonic development?

Gastrulation is a crucial phase in embryonic development where the initial single-layered blastula reorganizes into a multi-layered structure known as the gastrula. During this process, a significant movement of cells occurs, leading to the inward migration and differentiation of cells. This migration is essential as it establishes the three primary germ layers: the ectoderm, mesoderm, and endoderm, which will eventually give rise to all the tissues and organs of the organism.

This stage is critical because it sets the foundation for the body plan of the embryo, influencing further development and organizing the cells into the different functional systems. The formation of the gastrula marks a key transition from a simple cell mass to a more complex arrangement that will lead to the formation of various tissues and structures in the developing organism.