Fertilization And Prenatal Development

While the fertilized egg (zygote) over a period of 5-8 days to Nidationsort endometrial moves (usually near the fundus), it divides repeatedly. Until the time of implantation of the zygote has developed into a layer of cells around a cavity, called the blastocyst. Apart from the region of the embryonic pole, which is thick 3-4 cell layers, there is a Blastozystenwand from a cell series. The embryonic pole, which develops into the embryo implants itself first.

For fertilization (fertilization) is a vital sperm must unite with an egg in a tube with functionally intact epithelium. Fertilization occurs shortly after ovulation, about 14 days after a menstrual period. At the time of ovulation, the cervical mucus becomes less viscous and thus facilitates the rapid sperm forward movement toward the egg, which is usually located near the fimbriae of the tube. The sperm can remain active inside the vagina about 3 days after intercourse. While the fertilized egg (zygote) over a period of 5-8 days to Nidationsort endometrial moves (usually near the fundus), it divides repeatedly. Until the time of implantation of the zygote has developed into a layer of cells around a cavity, called the blastocyst. Apart from the region of the embryonic pole, which is thick 3-4 cell layers, there is a Blastozystenwand from a cell series. The embryonic pole, which develops into the embryo implants itself first. Amniotic cavity and placenta Within 1-2 days after the start of implantation developed to the blastocyst around a layer of cells (trophoblast cells). The precursor of the villous trophoblast cell, the stem cell of the placenta, designed to 2 cell lines: nonproliferative extravillous trophoblast: These cells invade the endometrium, facilitate the implantation and anchoring of the placenta. Syncytiotrophoblast: These cells produce chorionic gonadotropin from the 10th day and later other trophic hormones. From the trophoblasts, an inner (amnion) and an outer membrane layer (chorion) developed; These membranes form the membranes that the pregnancy product (a term that everything from the zygote Resulting in any phase of development-referred (placenta and embryo in about 11 4/7 weeks gestation.). If the sac formed and the cavity of the blastocyst has closed (after about 10 days), the product is designated as pregnancy embryo amniotic cavity fills with fluid and expands with the growing embryo, where it fills in about 12 weeks after fertilization, the uterine cavity;. is thereafter the amniotic cavity, the only remaining in the uterine cavity. placenta and embryo at the approximately 11 4/7 weeks of gestation. the embryo measures 4.2 cm. Trophoblast cells develop into the cells that form the placenta. The extravillous trophoblast form the villi, which penetrate into the uterus. The syncytiotrophoblast covers the villi. The syncytiotrophoblast synthesizes trophic hormones and ensures the arterial and venous exchange between the bloodstream of the conceptus and the mother. The placenta is in the 18.-20. Ausstrukturiert week, but grows even further up to a weight at term of approximately 500 g. Approximately embryo until 10 days have differentiated three germ layers (ectoderm, mesoderm, endoderm) in the embryo. Then the primitive streak from which the neural tube is formed to develop begins. Around day 16 thickens the cephalad specular component of the mesoderm, by forming a central channel, from which the heart and great vessels are formed. Around the 20th day, the heart starts pumping plasma, and the following day appear fetal red blood cells, which are immature and have a core. Fetal red blood cells are soon replaced by mature red blood cells, and arise anywhere in the embryo blood vessels. Finally, umbilical artery and umbilical vein connecting the embryonic blood vessels to the placenta develop. Most organs are formed between the 21st and 57th day after fertilization (5th-10th week of gestation.) From; the central nervous system (CNS) further but evolves throughout the course of pregnancy. Susceptibility to malformations by teratogenic influences during the formation of organs is the greatest.

Health Life Media Team

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