The Greek word zygoûn (which translates as "link" ) resulted in zygōtós ("United" ), which in turn came to our language as zygote or zygote . The zygote is called the cell that results from the fusion of the female gamete with the male gamete in the process of sexual reproduction that plants and animals develop.
From the term at hand, other equally important ones have emerged, such as the following:
-Heterozygous, which is used to refer to that cell that is formed from the union of two gametes that have different constitution.
-Homozygous, which is used to mention a cell that is created from the union of two gametes of identical constitution.
Also called egg , the zygote arises when the spermatozoon joins the Ovum . When their respective nuclei merge, the zygote nucleus emerges, which has two complete sets of chromosomes (one of each gamete). Organelles and cytoplasm, meanwhile, come from Ovum .
Once the zygote is formed, its segmentation , which includes successive mitoses to give rise to blastomeres (embryonic cells), which in turn give rise to the morula and then at blastula . In the continuity of embryonic development, the blastula becomes gastric and then in neurula . In this sequence the zygote is heading from the fallopian tube to him uterus .
The various phases of segmentation are known as blastulation , gastrulation and organogenesis . When the embryonic development concludes, the zygote is renamed fetus .
According to the location and level of vitelo (the substances that allow nutrition of the embryo), zygotes can be classified as centrolecitic (with great abundance of vitelo); telolecites ; mesolecitics or heterolecites ; and oligolecites or isolecites (with little window).
It is important to keep in mind that it is possible to differentiate in the zygote two large poles : he animal or germinative pole , which houses the nucleus and metabolic activity, and the vegetative pole where the mentioned vitelo accumulates.
It must be stated that it is very common to confuse the terms zygote, embryo and fetus. And they are used routinely to refer to a future baby on the way. However, it must be clear that they mention it but in the different phases of what would be their prenatal development:
-Cygote is the cell that arises when in fertilization the sperm and the egg fuse their nuclei. It usually has 46 chromosomes and its size is identical to that of the aforementioned ovule.
-Embryo is the one that occurs from the first day after fertilization until the eighth week of gestation.
-Fetus. In this case we can state that the end of the embryonic stage and the beginning of the fetal period is considered to take place from the 8th week of pregnancy. At this time it is considered that the embryo is already a fetus. That will make it grow while your vital organs are developing and it will acquire the appearance of a baby until it is born, which usually happens between weeks 38 and 40 of pregnancy, as a rule.