Definition of Placenta

1. Noun. That part of the ovary of a flowering plant where the ovules form.

Generic synonyms: Reproductive Structure
Group relationships: Ovary
Derivative terms: Placental



2. Noun. The vascular structure in the uterus of most mammals providing oxygen and nutrients for and transferring wastes from the developing fetus.
Terms within: Caul, Embryonic Membrane, Veil
Generic synonyms: Vascular Structure
Group relationships: Uterus, Womb
Specialized synonyms: Afterbirth
Derivative terms: Placental

Definition of Placenta

1. n. The vascular appendage which connects the fetus with the parent, and is cast off in parturition with the afterbirth.

Definition of Placenta

1. Noun. (anatomy) A vascular organ in mammals, except monotremes and marsupials, present only in the female during gestation. It supplies food and oxygen from the mother to the foetus, and passes back waste. It is implanted in the wall of the uterus and links to the foetus through the umbilical cord. It is expelled after birth. ¹

2. Noun. (botany) In flowering plants, the part of the ovary where ovules develop; in non-flowering plants where the spores develop. ¹

¹ Source: wiktionary.com

Definition of Placenta

1. a vascular organ in most mammals [n -TAS or -TAE]

Medical Definition of Placenta

1. An organ characteristic of true mammals during pregnancy, joining mother and offspring, providing endocrine secretion and selective exchange of soluble, but not particulate, blood borne substances through an apposition of uterine and trophoblastic vascularised parts. According to species, the area of vascular apposition may be diffuse, cotyledonary, zonary or discoid, the nature of apposition may be labyrinthine or villous, the intimacy of apposition may vary according to what layers are lost of those originally interposed between maternal and foetal blood (maternal endothelium, uterine connective tissue, uterine epithelium, chorion, extraembryonic mesoderm and endothelium of villous capillary). The chorion may be joined by and receive blood vessels from either the yolk sac or the allantois and the uterine lining may be largely shed with the chorion at birth (deciduate) or may separate from the chorion and remain (nondeciduate). The human placenta is discoid, villous, haemochorial, chorioallantoic and deciduate. After birth, it weighs about 600 gm. And is about 16 cm. In diameter and 2 cm. Thick, discounting a principal functional part, the maternal blood in the intervillous space (which leaks out at birth) into which the chorionic villi dip. The villi are grouped into adjoining cotyledons making about 20 velvety bumps on the side of the placenta facing outward to the uterus, the inner side of the placenta facing the foetus is smooth, being covered with amnion, a thin avascular layer that continues past the edges of the placenta to line the entire hollow sphere of chorion except where it is reflected to cover the umbilical cord, which joins foetus and placenta. The cord usually joins the placenta near the centre but may insert at the edge, on the nonplacental chorion or on an accessory placenta. (31 Dec 1997)

Placenta Pictures

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Lexicographical Neighbors of Placenta

placekicks
placeless
placelessly
placelessness
placeman
placemat
placemats
placemen
placement
placement center
placement office
placement test
placements
placename
placenames
placenta (current term)
placenta accreta
placenta accreta vera
placenta biloba
placenta bipartita
placenta circumvallata
placenta diffusa
placenta dimidiata
placenta duplex
placenta extrachorales
placenta fenestrata
placenta gonadotropin
placenta increta
placenta marginata
placenta membranacea

Literary usage of Placenta

Below you will find example usage of this term as found in modern and/or classical literature:

1. The American Journal of the Medical Sciences by Southern Society for Clinical Investigation (U.S.) (1899)
"In ordinary cases the placenta must be removed by the hand in but fa of 1 per ... The placenta in Triple Pregnancy.—In the American Journal of Obstetrics, ..."

2. Anatomy, Descriptive and Surgical by Henry Gray (1870)
"The placenta is the organ by which the connection between the foetus and mother is ... The villi of the chorion (or foetal placenta) gradually enlarge, ..."

3. The Lancet (1898)
"The Occurrence of a Vitelline placenta in the Suman Subject. Professor SIMPSON showed an Anencephalic Foetus which had been associated with marked ..."

4. Microscopical Morphology of the Animal Body in Health and Disease by Carl Heitzmann (1882)
"The placenta and the umbilical cord have been subjects of research iu my laboratory, ... It is acknowledged that the placenta represents a connective-tissue ..."

5. Surgery, Gynecology & Obstetrics by The American College of Surgeons, Franklin H. Martin Memorial Foundation (1921)
"The placenta in this case was shaped as follows: The cord was attached at a point about one inch from the margin of the placenta. Along the edge nearest to ..."

6. The American Journal of the Medical Sciences by Southern Society for Clinical Investigation (U.S.) (1899)
"In ordinary cases the placenta must be removed by the hand in but fa of 1 per ... The placenta in Triple Pregnancy.—In the American Journal of Obstetrics, ..."

7. Anatomy, Descriptive and Surgical by Henry Gray (1870)
"The placenta is the organ by which the connection between the foetus and mother is ... The villi of the chorion (or foetal placenta) gradually enlarge, ..."

8. The Lancet (1898)
"The Occurrence of a Vitelline placenta in the Suman Subject. Professor SIMPSON showed an Anencephalic Foetus which had been associated with marked ..."

9. Microscopical Morphology of the Animal Body in Health and Disease by Carl Heitzmann (1882)
"The placenta and the umbilical cord have been subjects of research iu my laboratory, ... It is acknowledged that the placenta represents a connective-tissue ..."

10. Surgery, Gynecology & Obstetrics by The American College of Surgeons, Franklin H. Martin Memorial Foundation (1921)
"The placenta in this case was shaped as follows: The cord was attached at a point about one inch from the margin of the placenta. Along the edge nearest to ..."

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