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Zygote, embryo, embryo, and fetus are commonly known concepts, but there are often disputes about when we are dealing with a fetus and when it is still an embryo. Does fertilization always lead to the formation of a zygote and implantation of the embryo in the uterine cavity? When does the zygote turn into an embryo?
Fertilization – what is it?
Fertilization is the process of connecting the reproductive cells, i.e. the egg and the sperm. This is a complex process that usually takes between 24 and 48 hours. Fertilization is possible between the tenth and eighteenth day of the menstrual cycle on average. For fertilization to take place, several important conditions must be met:
- there must be penetration, i.e. the man’s penis must go into the woman’s vagina. The chances of fertilization are much greater if you ejaculate during penetration. However, even without ejaculation, fertilization can occur because there are also live sperm in the pre-ejaculate;
- semen must travel through the cervix, the uterine cavity and the fallopian tube, where it usually fertilizes;
- the time frame must be met. Fertilization can take anywhere from several hours to several days. A woman’s sperm in the genital tract can live for about 70 hours, while the life span of an egg is about 12-24 hours. Therefore, fertilization depends on the timely alignment of male and female reproductive cells.
It is worth mentioning that over 50% of fertilized eggs undergo spontaneous miscarriage. Therefore, the process of fertilization itself is not synonymous with pregnancy and the further development of the zygote, embryo and fetus.
Zygote – what is formed after fertilization?
The zygote is the first cell to form after fertilization and contains a full set of chromosomes, because the sperm and egg both have half of them. In the following hours after fertilization, the first zygote divisions occur. Thanks to these divisions, a man is formed from the zygote. Cell division in the zygote occurs on average every 12-14 hours. In turn, the process of continuously dividing the zygote is called cleaving. The division of the zygote is a quick process because the first division takes place within 30 hours of fertilization. After another 60 hours, there are already 7-8 cells in the zygote. The cells of the zygote are called blastomers. After 3-4 days, there are about 12-16 blastomeres in the zygote, and the zygote itself begins to change shape, resembling a mulberry fruit.
The proper development of the child in the womb is supported by folic acid, which should be supplemented by every woman planning pregnancy and being pregnant after consulting a doctor. On Medonet Market you will find, for example, M-Folin SOLHERBS folic acid available in easily digestible form of pullulan capsules.
Zygote, Embryo, and Embryo – When Does Change Happen?
The embryo and the embryo are identical and mean the same thing. In the case of a human, the human embryo is said to be between the 4th and 8th week after fertilization. Once the zygote has established itself in the uterine cavity, the embryonic period begins. This is a very important period in the stages of the development of a future toddler, because it is during this time that the most important internal organs are formed and shaped. Among other things, the nervous system is formed. The embryo develops much faster than the zygote, cells divide very dynamically, and the most intensive multiplication takes place in the cells that are responsible for the formation of the brain, digestive system, bones, blood vessels, muscles and the previously mentioned nervous system. With the start of the 9th week of pregnancy, the developmental period of the fetus begins and lasts until delivery. This period is divided into trimesters in which the individual organs and systems that make up the human body develop.
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