Stage of development of the embryo from the moment of fertilization

Astana Medical University

IWS

Twins. Malformation of twins.

Prepared by: Laura Rais 226-GM

Cheked by: Gulmira Balmadinovna

Astana 2012 year

Plan

1. Types of twins

2. Symmetrical conjoined twins

3. Asymmetrical conjoined twins

4. References

Types of twins

It is well known that some twins are so similar that they are difficult to distinguish from each other, while other twins have extremely weak similarity to each other and are even different sexes. Less well known are the cause of the similar and dissimilar twins. The birth of two children in one pregnancy is largely a result of the allocation and the fertilization of two separate eggs. In these cases, children are called fraternal twins. They may be the same or different sex, may be similar or not similar to each other.

Twin monsters

Rare cases of identical twins, when they develop and are born fused together, are called "twinning deformities." The degree of fusion varies from weak connections surface tissues of two completely independent individuals to such a fusion, including the skeleton and internal organs of most of the body, only the head or only the lower parts of the body are separated. The location and angle of fusion are also different, and for many years the medical museums have accumulated a huge amount of these freaks. Any their classification.

Stage of development of the embryo from the moment of fertilization

Even if the known value of the embryo is initially formed in the germ cells, of which the embryo is formed, his life as a new individual is born after insemination. Age after fertilization in the human embryo which is at the medlaboratoriyu to study, almost never known, if not to take into account the most about information. Even if the fetus is accompanied by particularly accurate clinical materials, information as taken based solely on the efforts of the patient to recall the circumstances of their sexual activity recently. If we assume that the data of the start date of the last menstrual took place marked in the diary, yet not know the time of the sexual cycle, when the woman took ovulation. If for the sake of the integrity of the motives, we assume that the period of ovulation, accompanied by the release ready to fertilize the egg and the same congress, which became prosperous, are known, and we are able to determine the hours of fertilization, up from 12 to 24 hours. If the embryo with particularly detailed message about the history of the birth acquired as a result of unexpected termination of the pregnancy, it is still unclear the time of his death. We are not going to judge about how much time before the birth of his development stopped and there was death. Judging by the level of absorption of the body of the embryo, which is sometimes seen in the chorionic vesicles thrown out, no doubt, that the time interval between the death of the embryo and abortions can be substantial. Designated intervals too diversify in order to be able to formulate a fairly accurate assessment of their duration in each precedent. The most well-preserved embryos extracted with medical procedures. When naturally growing embryo isolated by a surgical procedure, we know with certainty at least an hour of his death.

All of the above highlights the particular importance of gathering as much as possible is especially true in the description of any precedent, where the process of intrauterine pregnancy should stop surgical abortion, and notes the crucial obtain this history together with carefully left embryo medlaboratorii for the survey, where the embryo is measuring, and then worked through other ways, essential to determine the extent of its formation. Exclusively in the study of all identified data, we can extend the reliability of our knowledge of the facts which occur in developing in the womb of existence.

Is of course arbitrary, but to present the most convenient to divide these twin monsters into two main categories: equal conjoined twins when both fused individual develops symmetrically and unequal conjoined twins, when one individual is much smaller than the other. The smaller member of this unequal pair usually has visible disabilities and its form suggests that it is an ugly parasite larger, normally developed twin.

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