The morula is a stage of development of an embryo.
The etymology of morula refers us to the scientific Latin morula , in turn derived from the Latin morum . This word refers to a "blackberry" .
The concept is used in the field of biology to refer to the stage of development of an embryo that follows the segmentation of the zygote and precedes the blastula . The term is linked to the appearance of the group of cells, similar to that of a blackberry.
Origin of morula
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 egg ) and the male gamete (the sperm ). This union leads to the fusion of the nuclei, making the zygote have two complete sets of chromosomes, each corresponding to a gamete.
As development progresses, the zygote undergoes segmentation that involves several cell divisions. The first phase of this process causes the cells resulting from division, known as blastomeres , to form the morula.
Its characteristics
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 formed by the union of between twelve and sixteen cells.
In the morula, all the replicating cells have the same size and identical shape. At this stage there is still no distinction between the organs .
Once the morula is formed, embryonic development continues until the formation of the blastula , which now has more than sixty-four cells. Then the embryo reaches the gastrula stage and later, the neurula stage.
The third week of pregnancy
Let's look at this concept from the point of view of a pregnancy, of the formation of a baby in its mother's womb. We must remember that during the third week, the mother still does not have sensations related to her child's development, although the process is already underway without rest . The aforementioned cell division takes place in the egg , approximately thirty hours after its fertilization, starting with two parts, followed by four, eight, and so on, as it moves through the fallopian tube on its journey to the uterus.
After the segmentation of the zygote, the blastomeres form the morula.
And it is there, in the uterus, where this group of cells is seen as a small ball that scientists call "morula." Later, it becomes hollow and its interior receives a certain amount of liquid. In this instance, we stop talking about "morula" and move on to "blastocyte." At the end of the third week, the blastocyst attaches to the wall of the uterus , known as the “endometrium,” in a process called “implantation.” This is a fundamental connection, because from there come the nutrients that the embryo needs to develop and it also fulfills the function of eliminating waste.
It is important to note that the morula does not always manage to nest in the cavity of the uterus, but its path can be interrupted by different obstacles . Such is the case of the maternal tubes, malformations in the uterus itself or even the counterproductive action of sexual hormones, which can interrupt pregnancy. Many pregnancies fail in this phase; One of the common causes is incorrect implantation of the embryo, which can occur outside the uterus.