placentation

placentation

 [plas″en-ta´shun]

the series of events following implantation of the embryo and leading to development of the placenta.

plac·en·ta·tion

(plas'en-tā'shŭn),

The structural organization and mode of attachment of fetal to maternal tissues in the formation of the placenta. Types of placentation are defined under placenta.

placentation

/pla·cen·ta·tion/ (pla″sen-ta´shun) the series of events following implantation of the embryo and leading to development of the placenta.

placentation

(plăs′ən-tā′shən)

n.

a. Formation of a placenta in the uterus.

b. The type or structure of a placenta.

placentation

Obstetrics The formation of the placenta in the uterus; the process by which a placenta grows and develops in the uterus. See Extrachorial placentation.

plac·en·ta·tion

(plas'en-tā'shŭn)

The structural organization and mode of attachment of fetal to maternal tissues in the formation of the placenta.

placentation

the arrangement of PLACENTAS (2) in the plant ovary, which can be classified into several categories including:

1. (a) apical, at the ovary apex,
2. (b) basal, at the ovary base,
3. (c) parietal, on the ovary wall,
4. (d) free-central, on a column growing up from the ovary base.

placentation

1. the series of events following implantation of the embryo and leading to development of the placenta.

2. the nature of the implantation. See also placenta.

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adventitial placentation

developmental of additional areas outside the normal areas, e.g. intercotyledonary in cattle.

cotyledonary placentation

the areas of placentation are limited to caruncles, approximately circular masses scattered over the placenta. Characteristic of the cow, ewe and goat doe.

diffuse placentation

the whole of the surface of the chorion is placental.

intercotyledonary placentation

abnormal placental attachments between the cotyledons, in cows.

zonal placentation

only some zones of the placenta have a vascular area involved in placentation. Characteristic of the bitch and the queen.

Zonary placenta of carnivores. By permission from Sack W, Wensing CJG, Dyce KM, Textbook of Veterinary Anatomy, Saunders, 2002