The etymology from morula refers us to scientific Latin morula, in turn derived from Latin morum. This word refers to a “Blackberry”.
The concept is used in the field of biology to allude to the developmental stage of an embryo that follows segmentation of the zygote and precedes the blastula. The term is linked to the appearance of the set of cells, similar to that of a blackberry.
It is important to remember that, in the sexual reproduction of an organism, the zygote or egg arises from the union of the female gamete (the Ovum) and the male gamete (the spermatozoon). This union leads to the fusion of the nuclei, causing the zygote to have two complete sets of chromosomes, each corresponding to a gamete.
As development proceeds, the zygote undergoes a segmentation which involves various cell divisions. The first phase of this process causes the cells resulting from division, known as blastomeres, form the morula.
Therefore, it can be said that the morula is a mass of cells that is generated from the segmentation of the zygote. The morula occurs between two and four days after the beginning of cell segmentation and is usually constituted by the union of between twelve and sixteen cells.
In the morula, all the replicating cells are the same size and shape. At this stage there is still no distinction between organs.
Once the morula is constituted, embryonic development continues until the formation of the blastula, which already has more than sixty-four cells. Then he embryo reaches the stage of gastrula and later, that of neurula.