placenta

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placenta

placenta or afterbirth, organ that develops in the uterus during pregnancy. It is a unique characteristic of the higher (or placental) mammals. In humans it is a thick mass, about 7 in. (18 cm) in diameter, liberally supplied with blood vessels. The placenta is attached to the uterus, and the fetus is connected to the placenta by the umbilical cord. The placenta draws nourishment and oxygen, which it supplies to the fetus, from the maternal circulation. In turn, the placenta receives the wastes of fetal metabolism and discharges them into the maternal circulation for disposal. It also acts as an endocrine gland, producing estrogen, progesterone, and gonadotrophin. Shortly after delivery of the fetus the placenta is forced out by contractions of the uterus. Severe hemorrhage may occur if the placenta does not emerge in its entirety or if the uterus fails to contract properly.

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"placenta." The Columbia Encyclopedia, Sixth Edition. 2008. Encyclopedia.com. 20 Dec. 2009 <http://www.encyclopedia.com>.

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placenta

A Dictionary of Plant Sciences | 1998 | | Â© A Dictionary of Plant Sciences 1998, originally published by Oxford University Press 1998. (Hide copyright information) Copyright

placenta In flowers, the part of the ovary wall formed from the fused margins of the carpel or carpels, on which are carried the ovules.

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MICHAEL ALLABY. "placenta." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. 20 Dec. 2009 <http://www.encyclopedia.com>.

MICHAEL ALLABY. "placenta." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. (December 20, 2009). http://www.encyclopedia.com/doc/1O7-placenta.html

MICHAEL ALLABY. "placenta." A Dictionary of Plant Sciences. 1998. Retrieved December 20, 2009 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O7-placenta.html

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placenta

A Dictionary of Zoology | 1999 | | Â© A Dictionary of Zoology 1999, originally published by Oxford University Press 1999. (Hide copyright information) Copyright

placenta In animals, the organ by which embryos of viviparous species are nourished and waste products removed, formed by the fusion of embryonic and maternal tissues.

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MICHAEL ALLABY. "placenta." A Dictionary of Zoology. 1999. Encyclopedia.com. 20 Dec. 2009 <http://www.encyclopedia.com>.

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MICHAEL ALLABY. "placenta." A Dictionary of Zoology. 1999. Retrieved December 20, 2009 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O8-placenta.html

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	Placenta accreta Magazine article from: Archives of Pathology & Laboratory Medicine; 12/1/2002; ; 700+ words ; ...fetus was delivered safely; the placenta, however, was markedly adherent...examination of the gross specimen showed placenta markedly adherent to myometrium...so that clear distinction between placenta and myometrium was blurred. We...
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	New Placenta Previa Definitions Advocated. Magazine article from: OB GYN News; 9/1/2001; ; 700+ words ; ...pregnant women need a double set-up exam for placenta previa? That depends on both how placenta previa is defined and the degree of previa...some radiologists might define a marginal placenta previa as the placental edge being at the...
	Customary release of placentas demanded Newspaper article from: Honolulu Star - Bulletin; 2/11/2006; ; 700+ words ; ...Health was not aware placentas were being released...take their baby's placenta, said state Health...their child's placenta. Meanwhile, Fukino...to take not only placentas, but other body...taking home the placentas from their two oldest...could not have the placenta, Kihapai Krug ...