mórula

A mórula is an early stage of embryonic development in animals. It follows the morula stage, which is a solid ball of cells formed by cleavage of a zygote. The mórula is characterized by the presence of a cavity within this ball of cells called the blastocoel. The cells within the mórula are still undifferentiated, meaning they have not yet specialized into distinct cell types.

The formation of the mórula is a crucial step in embryogenesis. As the zygote undergoes rapid cell divisions (cleavage), it forms a blastula. In many species, the blastula stage is synonymous with the mórula, where the outer layer of cells forms the trophectoderm and the inner cell mass develops. The trophectoderm will eventually contribute to the placenta, while the inner cell mass will give rise to the embryo proper.

The process of blastulation, leading to the mórula, involves both cell division and cellular rearrangement. The cells of the early embryo secrete fluid into the interior, creating the blastocoel. This fluid-filled cavity is essential for the subsequent development of the embryo, as it provides space for cell migration and differentiation. The mórula stage is a prelude to gastrulation, the process where the three primary germ layers (ectoderm, mesoderm, and endoderm) are formed, which will eventually differentiate into all the tissues and organs of the developing organism. The exact appearance and composition of the mórula can vary between different animal species.