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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 ...
Manual placenta removal is the evacuation of the placenta from the uterus by hand. [6] It is usually carried out under anesthesia or more rarely, under sedation and analgesia . A hand is inserted through the vagina and cervix into the uterine cavity and the placenta is detached from the uterine wall and then removed manually.
Placenta can also be divided according to what kind of structure it develops from. There are two vessel-rich features in the amniote, the yolk sac and the allantois. When the chorion fuses with the former, the result is a choriovitelline placenta. When it fuses with the latter, the result is a chorioallantoic placenta.
Image showing trophoblast differentiated into the two layers of cytotrophoblast and syncytiotrophoblast during implantation. It is the outer layer of the trophoblasts and actively invades the uterine wall, during implantation, rupturing maternal capillaries and thus establishing an interface between maternal blood and embryonic extracellular fluid, facilitating passive exchange of material ...
The placenta also produces human placental lactogen (hPL), which stimulates maternal lipolysis and fatty acid metabolism. As a result, this conserves blood glucose for use by the fetus. It can also decrease maternal tissue sensitivity to insulin, resulting in gestational diabetes.
The average time from delivery of the baby until complete expulsion of the placenta is estimated to be 10–12 minutes dependent on whether active or expectant management is employed. [53] In as many as 3% of all vaginal deliveries, the duration of the third stage is longer than 30 minutes and raises concern for retained placenta. [54]
Retained placenta fragments is an outcome of failure in the complete expulsion of the placenta, and contributes to DOL. [13] [17] Residual portions of the placenta continue to secrete progesterone, which inhibits progesterone withdrawal and subsequently hinders the initiation of lactogenesis II.
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 resulting in the presence of shunts to move oxygenated blood and ...