placentation

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plac·en·ta·tion

 (plăs′ən-tā′shən)
n.
1.
a. Formation of a placenta in the uterus.
b. The type or structure of a placenta.
2. Botany Arrangement of placentas within the ovary.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

placentation

(ˌplæsɛnˈteɪʃən)
n
1. (Botany) botany the way in which ovules are attached in the ovary
2. (Zoology) zoology
a. the way in which the placenta is attached in the uterus
b. the process of formation of the placenta
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.placentation - the formation of the placenta in the uterus
bodily function, bodily process, body process, activity - an organic process that takes place in the body; "respiratory activity"
2.placentation - arrangement of the ovules in the placenta and of the placentas in the ovary
reproductive structure - the parts of a plant involved in its reproduction
apical placentation - where one or few ovules develop at the top of a simple or compound ovary
axile placentation - ovules are borne at or around the center of a compound ovary on an axis formed from joined septa
basal placentation - where one or few ovules develop at the base of a simple or compound ovary
free central placentation - where ovules develop on a central column in a compound ovary lacking septa or with septa at base only
lamellate placentation - with ovules on thin extensions of the placentae into a compound ovary
marginal placentation, ventral placentation - with ovules borne on the wall along the ventral suture of a simple ovary
parietal placentation - where ovules develop on the wall or slight outgrowths of the wall forming broken partitions within a compound ovary
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
This may be due to differences in implantation and placentation in pigs, which forms a non-invasive true epitheliochorial type placenta and does not require a decidualization process during the implantation period, whereas in humans and rodents the endometrium is decidualized for implantation and an invasive hemochorial type placenta is formed when the embryo is implanted.
Since both rabbit and human have the same hemochorial type of placenta (Chesne et al., 2002).
Defective hemochorial placentation as a cause of miscarriage, a preliminary study.Br J ObstetGynaecol 1987; 94: 649.
[1] Human placenta is described as hemochorial, discoid, and deciduate; at term, mean placental weight is 470 g, diameter ranges from 200 to 220 mm, and thickness is 25 mm.
As the placentation in rats is of hemochorial type, i.e., the trophoblast is in direct contact with maternal bloodstream, the trophoblast invasion is necessary.