What is a morula?

A morula is a significant stage in the early development of an embryo and refers specifically to the structure that forms following the cleavage of a fertilized egg (zygote). After several rounds of cell division, known as mitosis, the zygote transforms into a solid ball of cells, typically consisting of 16 to 32 cells. This stage occurs before the formation of the blastocyst and is important in the early stages of development.

The morula stage represents a period where the cells are still undifferentiated, meaning they have not yet begun to form the various cell types that will develop into the different tissues and organs of the fetus. This stage precedes the blastocyst, which is the structure that eventually implants into the uterine wall.

Understanding what a morula is helps clarify the entire developmental process, as it's a crucial intermediary step leading to the formation of a blastocyst.