gastrulácia

Gastrulácia, commonly translated as gastrulation, is a key phase of embryonic development during which the embryo transitions from a relatively simple blastula composed of a single cell layer to a multi-layered structure called the gastrula. This restructuring establishes the three primary germ layers: ectoderm, mesoderm, and endoderm, which give rise to all tissues and organs.

During gastrulácia, cells move and reorganize through processes such as invagination, where a cell sheet indents inward; involution, where a sheet spreads over the internal surface; delamination, where cells separate into new layers; and epiboly, where cell sheets spread to cover the embryo. The interior cavity becomes the archenteron, and the opening to the exterior forms the blastopore. In deuterostomes (including vertebrates), the archenteron develops into the gut, while in protostomes the blastopore becomes the mouth.

Gastrulácia also establishes the basic body axes and sends signals that induce tissue-specific differentiation. Gene networks involving signaling pathways such as Wnt, Nodal, and BMP coordinate cell movements and fate specification, giving rise to ectoderm (outer layer), mesoderm (middle layer), and endoderm (inner layer). The timing and mode of gastrulation vary among species: amphibians often rely on a dorsal lip organizer and extensive cell movements; birds and mammals use a primitive streak with epibolic movements.

Errors in gastrulácia can lead to congenital anomalies. Understanding gastrulácia provides essential insight into how the embryo differentiates and the initial steps toward organ formation.