blastulación

Blastulación is a crucial stage in early embryonic development. Following fertilization, the zygote undergoes a series of rapid cell divisions known as cleavage. This process results in a multicellular structure that, by the blastula stage, forms a hollow ball of cells called the blastocyst. The outer layer of the blastocyst is termed the trophoblast, which will eventually contribute to the placenta. Inside the trophoblast is a fluid-filled cavity known as the blastocoel. Within the blastocoel, clustered at one pole, is the inner cell mass, which will give rise to the embryo proper. The formation of the blastula is a universal process observed in the development of most animals, though the specific structures and timing can vary between species. This stage marks a significant increase in cell number and the establishment of distinct cell lineages. The blastula is the precursor to gastrulation, the next major developmental event where the three primary germ layers are formed. The process is essential for organizing the developing organism and preparing it for further differentiation and tissue formation.