Conception is called biological process with which pregnancy begins. Conception in a womb of the woman is resulted by a germ from which the full-fledged, viable human individual will be created.
In ordinary consciousness the conception is quite often identified with sexual intercourse. Considering that sexual intercourse takes several minutes, conception is considered "minute business" too. Such representation does not correspond to reality: conception – rather long process which is not synchronizing sexual intercourse of which conception is result.
Conception includes three stages: fertilization, crushing and implantation.
Fertilization
The main maintenance of a stage of fertilization is "meeting" of a spermatozoon with an ovum. It occurs approximately in 2 hours after hit of sperm in a vagina – such time is necessary for a spermatozoon to reach that part of a fallopian pipe which directly adjoins an ovary there is a ripened ovum.
When the spermatozoon gets into an ovum, its cover collapses, there is a zygote – a special cage with two pronukleusa (the kernels having an unary set of chromosomes). The process of rapprochement of pronukleus which is coming to the end with their merge borrows more than a day – 26-30 hours.
Crushing
The maintenance of a stage of crushing – division of a zygote and the subsequent division of daughter cells, and every time daughter cells happen less maternal by the size. The cages which are formed at this stage are called blastomer. The stage of crushing lasts several days. "The significant event" takes place for the 4th day when the number of blastomer reaches 16: cages which still did not differ from each other are for the first time differentiated – some cages form embrioblast (an embryo prototype), and others – an outer layer which for the 5th day forms a spherical cover. So arises the blastotsit which will develop some more days.
Implantation
While there is a crushing, there is no blastotsit left on the place: reductions of a fallopian pipe gradually advance it towards a uterus. It is possible to tell without exaggeration that this way is difficult and dangerous: only one germ from ten is capable to endure it! For this reason women sometimes have delays of menstruation which pregnancy does not follow. The germ will reach a uterus for the 11th day after fertilization. Now it has to be attached to an internal cover of a uterus – to endometrium, it also is called implantation. That it occurred, the cover of a germ has to break then it will have finger-shaped shoots. This process takes about 40 hours. Thus, the general duration of conception at the person – from the beginning of fertilization before completion of implantation of a germ in a uterus – is about 12.5-13 days, nearly two weeks.