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  2. Placenta - Wikipedia

    en.wikipedia.org/wiki/Placenta

    The placenta (pl.: placentas or placentae) is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation.It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate maternal and fetal circulations, and is an important endocrine organ, producing hormones that regulate both maternal and fetal ...

  3. Placentation - Wikipedia

    en.wikipedia.org/wiki/Placentation

    In humans, placentation takes place 7–8 days after fertilization. In humans, the placenta develops in the following manner. Chorionic villi (from the embryo) on the embryonic pole grow, forming chorion frondosum. Villi on the opposite side (abembryonic pole) degenerate and form the chorion laeve (or chorionic laevae), a smooth surface. The ...

  4. Trophoblast - Wikipedia

    en.wikipedia.org/wiki/Trophoblast

    Trophoblasts are specialized cells of the placenta that play an important role in embryo implantation and interaction with the decidualized maternal uterus. [5] The core of placental villi contain mesenchymal cells and placental blood vessels that are directly connected to the fetus’ circulation via the umbilical cord.

  5. Fetal circulation - Wikipedia

    en.wikipedia.org/wiki/Fetal_circulation

    In humans, the circulatory system is different before and after birth. The fetal circulation is composed of the placenta, umbilical blood vessels encapsulated by the umbilical cord, heart and systemic blood vessels. A major difference between the fetal circulation and postnatal circulation is that the lungs are not used during the fetal stage ...

  6. Category:Placenta - Wikipedia

    en.wikipedia.org/wiki/Category:Placenta

    Articles relating to the placenta, a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation.It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate maternal and fetal circulations, and is an important endocrine organ, producing hormones that regulate both maternal and fetal physiology ...

  7. Placental cotyledon - Wikipedia

    en.wikipedia.org/wiki/Placental_cotyledon

    The form of the human placenta is generally classified as a discoid placenta. Within this, the cotyledons are the approximately 15-25 separations of the decidua basalis of the placenta, separated by placental septa. [3] Each cotyledon consists of a main stem of a chorionic villus as well as its branches and sub-branches. [3]

  8. Yolk sac - Wikipedia

    en.wikipedia.org/wiki/Yolk_sac

    [4] [5] Before the placenta is formed and can take over, the yolk sac provides nutrition and gas exchange between the mother and the developing embryo. [ 6 ] At the end of the fourth week, the yolk sac presents the appearance of a small pear-shaped opening (traditionally called the umbilical vesicle ), into the digestive tube by a long narrow ...

  9. Pregnancy hormones - Wikipedia

    en.wikipedia.org/wiki/Pregnancy_hormones

    Human Chronic Gonadotropin (hCG) is produced from the placenta after the implantation of a fertilized egg in the uterus. [2] Fused villous syncytiotrophoblast cells and extravillous invasive cytotrophoblast cells make hCG. [2] hCG promotes the production of corpus luteal progesterone [2] which helps to maintain the corpus luteum for producing ...