placenta
American Heritage Dictionary:
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pla·cen·ta
(plə-sĕn'tə) 
n., pl., -tas, or -tae (-tē).
n., pl., -tas, or -tae (-tē).
- A membranous vascular organ that develops in female mammals during pregnancy, lining the uterine wall and partially enveloping the fetus, to which it is attached by the umbilical cord. Following birth, the placenta is expelled.
- An organ with similar functions in some nonmammalian animals, such as certain sharks and reptiles.
- Botany. The part within the ovary of a flowering plant to which the ovules are attached.
[New Latin, from Latin, flat cake, alteration of Greek plakoenta, from accusative of plakoeis, flat, from plax, plak-, flat land, surface.]
placental pla·cen'tal adj.Britannica Concise Encyclopedia:
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placenta
Organ in most mammals that develops in the uterus along with a fetus to mediate metabolic exchange. The umbilical cord attaches it to the fetus at the navel. Nutrients and oxygen in the mother's blood pass across the placenta to the fetus, and metabolic wastes and carbon dioxide from the fetus cross in the other direction; the two blood supplies do not mix. Other substances (e.g., alcohol or drugs) in the mother's blood can also cross the placenta, with effects including congenital disorders and drug addiction in the newborn ( fetal alcohol syndrome); some microorganisms can cross it to infect the fetus, but so do the mother's antibodies. The placenta, weighing a pound or more at the end of pregnancy, is expelled at parturition. Some animals eat it as a source of nutrients; in some species this stimulates lactation.
For more information on placenta, visit Britannica.com.
Oxford Companion to the Body:
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placenta
The placenta forms from both embryonic and maternal tissues, and hosts an astonishing array of hormonal, nutritional, respiratory, excretory, and immunological functions. It is expelled after the baby as the ‘afterbirth’.
When the developing, fertilized egg at the ‘blastocyst’ stage becomes implanted in the lining of the uterus, it develops ‘villi’ — fine, frond-like cellular projections from its outermost layer, the trophoblast. It is initially through these villi that nutrients are absorbed. Then, as the embryonic circulatory system develops, blood vessels grow into the villi on the implanted side of the embryo; this becomes the fetal component of the placenta. The nutritional functions of the placenta become concentrated in the intervillous space, which is bathed by the mother's blood from the spiral arteries, which are branches of the arteries to the uterus. The spiral arteries are converted in early to mid pregnancy, by trophoblast (placental) cell invasion, to become blood vessels that more resemble veins than arteries. (If this process does not occur, then the pregnancy may become complicated by pre-eclampsia, a condition characterized by high blood pressure and protein in the urine.) Normal, converted spiral arteries ensure steady supply of blood in a low-resistance circulation. Glucose and amino acids in the mother's blood pass to capillary blood vessels in the fetal villi that dangle in the intervillous space, covered only by a thin membrane, and from them pass to the fetus, through the umbilical vein in the umbilical cord, to be used as building blocks for intrauterine growth.
The placenta. The fetal (umbilical) arteries and their branches are shown white, and the vein and its branches black
At this same interface between mother and fetus, gas exchange occurs, with passage of oxygen to the fetus, and carbon dioxide to the mother. Thus, the placenta fulfils in intrauterine life the functions of the lungs after birth. A low concentration of oxygen in fetal blood encourages this direction of transfer, together with the particular nature of fetal haemoglobin.
Similarly, the placenta has equivalent functions to the kidney after birth in permitting the excretion of the biochemical waste products of metabolism. There are fetuses that develop without kidneys (a condition known as renal agenesis). Because of the function of the placenta they often survive until birth, although they cannot survive long thereafter.
Although one might expect the placenta to be rejected by the mother's immune system, because the fetal component is ‘foreign’, this does not happen, because of the presence of unique antigens on the cell surfaces.
In addition to these functions of exchange between the two individual blood streams, the placenta also produces an extensive array of hormones. These include human chorionic gonadotropin (HCG) produced by embryonic tissue right from the time of implantation: this promptly protects the embryo from rejection, by acting on the ovaries, causing them to sustain the hormone production that supports pregnancy. The presence of HCG also acts as the basis of pregnancy testing. After the third month, hormone production by the placenta takes over the pregnancy-supporting role from the ovary, by virtue of progressively increasing secretion of oestrogens and progesterone.
Growth of the fetus may be impaired if the placenta malfunctions. If the degree is severe, oxygenation may also become impaired, ultimately with death of the fetus and stillbirth. Other clinical problems associated with the placenta are placenta praevia, in which the placenta is located below the fetus, and placental abruption, in which the placenta separates prematurely from the wall of the uterus. Both of these conditions may be associated with brisk haemorrhage.
The placenta is ejected during the third stage of labour.
— Jim Neilson
See also antenatal development; labour; ovary; uterus; sex hormones.
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The information on popular childbirth practices is too inadequate to allow us to judge whether the placenta was always formally disposed of (not just thrown away), but this seems likely. In 20th-century midwifery, the official rule was to burn it—on the fire in the living-room or bedroom for home deliveries, in an incinerator at hospital. Some said one could tell how many more children the woman would have by counting the pops it made while burning; Aubrey said midwives predicted how long a baby would live by burning the afterbirth (Aubrey, 1686/1880: 73).
Nowadays, women who give birth at home sometimes choose to have the placenta buried in the garden, with a shrub planted over it. This is a revival of an older custom, with continental parallels (Gélis, 1991: 167-71); some informants recall the practice from before the Second World War, and add that a placenta was the best possible fertilizer for rose bushes [JS]. Others eat the placenta as a natural medicine to avoid post-natal depression, and this too may have a traditional basis, since French evidence suggests that it was sometimes eaten to encourage lactation (Gélis, 1991: 167-71). The National Childbirth Trust recently published a book, Placenta Special: Eat It or Plant It?, since it is ‘a frequent topic among young mothers’ (Independent (27 Nov. 1998), 3). A placenta can also serve as a dressing to promote healing of pressure sores and deep ulcers, and be rubbed on the mother's breasts to prevent chapping when breast-feeding [JS].
In 19th-century Cheshire, some men believed they ‘could gain the affections of a woman almost against her will by burying a placenta at the threshold of her house. This was actually done within living memory at Gatley (Cheshire) by a man named Gatley, he having procured one for two guineas. The charm failed in this instance, the woman being very self-willed’ (Moss, 1898: 169).
Some farmers disposed of a cow's or mare's placenta by hanging it in a hawthorn tree. In Hampshire in the 1930s this was done ‘as a preventative of fever in the cow’ (Vickery, 1995: 170); on a farm in Bilsdale (Yorkshire) it is still being done, to bring luck to newborn foals (FLS News 28 (1998)). They may also have wanted to thwart the animal's instinct to eat her afterbirth if (as in France) they feared she would then eat her offspring too (Gélis, 1991: 166).
Columbia Encyclopedia:
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placenta
placenta (pləsĕn'tə) 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, gonadotrophin, and serotonin. 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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(pluh-sen-tuh)
An organ that forms in the uterus after the implantation of a zygote. The placenta moves nourishment from the mother's blood to the embryo or fetus; it also sends the embryo or fetus's waste products into the mother's blood to be disposed of by the mother's excretory system. The embryo or fetus is attached to the placenta by the umbilical cord. After birth, the placenta separates from the uterus and is pushed out of the mother's body.
Oxford Dictionary of Biochemistry:
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placenta
(pl. placentas or placentae)
a highly vascularized organ within the uterus of a pregnant animal by which the embryo is attached to the uterine wall and through which the embryo can exchange solutes with the maternal circulation. The placenta also functions as an endocrine gland, secreting inter alia choriogonadotropin, choriomammotropin, and certain steroid hormones.
—placental adj.
a highly vascularized organ within the uterus of a pregnant animal by which the embryo is attached to the uterine wall and through which the embryo can exchange solutes with the maternal circulation. The placenta also functions as an endocrine gland, secreting inter alia choriogonadotropin, choriomammotropin, and certain steroid hormones.
—placental adj.
| placebo, pixel, pituitary gland | |
| placental lactogen, placental ribonuclease inhibitor, plakoglobin |
Saunders Veterinary Dictionary:
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placenta
Pl. placentae, placentas [L.] an organ characteristic of true mammals during pregnancy, joining mother and offspring, providing endocrine secretion and selective exchange of soluble bloodborne substances through apposition of uterine and trophoblastic vascularized parts. Called also afterbirth. See also fetal membranes, placentation.
Domestic animals have a chorioallantoic placenta in which the outer layer of the allantois is fused with the chorion and the fetal umbilical vessels are distributed in the connective tissue between the two. Placentae are classified in several ways; based on the tissues of the dam and the fetus that contact each other; based on the proportion of the surface area of the fetal membranes that is in fact placentacious; based on loss of tissue at birth, etc. Thus the bovine placenta is epitheliochorial, cotyledonary and nondeciduate.
The major function of the placenta is to allow diffusion of nutrients from the dam's blood into the fetus's blood and diffusion of waste products from the fetus back to the dam. This two-way exchange takes place across the placental membrane, which is semipermeable. The placenta also produces hormones such as progesterone and estrogen.
- choriovitelline p. — a placentation in which the yolk sac becomes involved in the fetal–maternal union.
- cotyledonary p. — distribution of the villi on the fetal chorion is localized in multiple circumscribed areas—the cotyledons.
Cotyledonary placenta of ruminants. By permission from Sack W, Wensing CJG, Dyce KM, Textbook of Veterinary Anatomy, Saunders, 2002 - diffuse p. — the villi on the fetal chorion is diffuse over the entire placenta as in mares and sows.
- discoid p. — a placenta in which the chorionic villi are arranged in a circular plate as in human and rodent placentae.
- endotheliochorial p. — the maternal vessels in the endometrium are bared to their endothelium and these are in contact with the chorion of the fetal membranes. This occurs in the bitch and queen.
- epitheliochorial p. — the uterine epithelium of the uterus and the chorion are in contact in this placentation, and there is no erosion of the epithelium. Characteristic of cows, sows and mares. Called also adeciduate placenta.
- hemochorial p. — a type of placenta in which all maternal layers are lost so that fetal tissue is in contact with frank maternal blood, as occurs in insectivores, rodents, rabbits and most primates.
- nondeciduate p. — no maternal tissue is lost when the pregnancy terminates.
- retained p. — the placenta has not been passed within 12 hours after the fetus has been delivered. Represents a potential beginning for metritis and infertility. Often difficult to assess in carnivores which rapidly eat the placenta.
- syndesmochorial p. — a type of placentation characterized by an endometrial attachment to the chorion with a limited amount of destruction of the endometrial epithelium. Formerly thought to be characteristic of the ewe and goat doe, these species are now known to have epitheliochorial placentae.
- zonary p. — a placenta in which the chorionic villi are restricted to an equatorial girdle, as in the bitch and queen.
Mosby's Dental Dictionary:
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placenta
n
The organ of metabolic interchange between the fetus and the mother.
Random House Word Menu:
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categories related to 'placenta'
- Reproductive System - placenta: vascular organ that surrounds fetus and unites it with uterus for nutrition
- Reproduction and Development - placenta: organ for nourishing embryo and removing waste products in most mammals
- Pregnancy and Birth - placenta: structure within uterus connected to umbilical cord through which fetus receives nourishment and eliminates feces
Wikipedia on Answers.com:
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Placenta
For the ancient Roman bread, see placenta (food). For the placenta of fruit, see placentation.
| Placenta | |
|---|---|
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| Placenta | |
| Precursor | decidua basalis, chorion frondosum |
| Code | TE E5.11.3.1.1.0.5 |
The placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply. "True" placentas are a defining characteristic of eutherian or "placental" mammals, but are also found in some snakes and lizards with varying levels of development up to mammalian levels.[1] Note, however, that the homology of such structures in various viviparous organisms is debatable at best and, in invertebrates such as Arthropoda, is definitely analogous at best. However, a recent publication describes what amounts to a phylogenetically analogous, but physiologically and functionally almost identical structure in a skink. In some senses it is not particularly surprising, because many species are ovoviviparous and some are known as examples of various degrees of viviparous matrotrophy. However, the latest example is the most extreme to date, of a purely reptilian placenta directly comparable to a eutherian placenta.[2]
The word placenta comes from the Latin word for cake, from Greek plakóenta/plakoúnta, accusative of plakóeis/plakoús – πλακόεις, πλακούς, "flat, slab-like",[3] in reference to its round, flat appearance in humans. The classical plural is placentae, but the form placentas is common in modern English and probably has the wider currency at present.
Prototherial (egg-laying) and metatherial (marsupial) mammals produce a choriovitelline placenta that, while connected to the uterine wall, provides nutrients mainly derived from the egg sac.
The placenta functions as a fetomaternal organ with two components: the fetal placenta, or (Chorion frondosum), which develops from the same sperm and egg cells that form the fetus; and the maternal placenta, or (Decidua basalis), which develops from the maternal uterine tissue.[4]
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Structure
In humans, the placenta averages 22 cm (9 inch) in length and 2–2.5 cm (0.8–1 inch) in thickness (greatest thickness at the center and become thinner peripherally). It typically weighs approximately 500 grams (1 lb). It has a dark reddish-blue or maroon color. It connects to the fetus by an umbilical cord of approximately 55–60 cm (22–24 inch) in length that contains two arteries and one vein.[5] The umbilical cord inserts into the chorionic plate (has an eccentric attachment). Vessels branch out over the surface of the placenta and further divide to form a network covered by a thin layer of cells. This results in the formation of villous tree structures. On the maternal side, these villous tree structures are grouped into lobules called cotyledons. In humans, the placenta usually has a disc shape, but size varies vastly between different mammalian species.[6]
Development
Further information: Placentation
The placenta begins to develop upon implantation of the blastocyst into the maternal endometrium. The outer layer of the blastocyst becomes the trophoblast, which forms the outer layer of the placenta. This outer layer is divided into two further layers: the underlying cytotrophoblast layer and the overlying syncytiotrophoblast layer. The syncytiotrophoblast is a multinucleated continuous cell layer that covers the surface of the placenta. It forms as a result of differentiation and fusion of the underlying cytotrophoblast cells, a process that continues throughout placental development. The syncytiotrophoblast (otherwise known as syncytium), thereby contributes to the barrier function of the placenta.
The placenta grows throughout pregnancy. Development of the maternal blood supply to the placenta is complete by the end of the first trimester of pregnancy (approximately 12–13 weeks).
Placental circulation
Maternal placental circulation
In preparation for implantation, the uterine endometrium undergoes 'decidualisation'. Spiral arteries in decidua are remodeled so that they become less convoluted and their diameter is increased. The increased diameter and straighter flow path both act to increase maternal blood flow to the placenta. The relatively high pressure as the maternal blood fills intervillous space through these spiral arteries bathes the fetal villi in blood, allowing an exchange of gases to take place. In humans and other hemochorial placentals, the maternal blood comes into direct contact with the fetal chorion, though no fluid is exchanged. As the pressure decreases between pulses, the deoxygenated blood flows back through the endometrial veins.
Maternal blood flow is approx 600–700 ml/min at term.
Fetoplacental circulation
Further information: Fetal circulation
Deoxygenated fetal blood passes through umbilical arteries to the placenta. At the junction of umbilical cord and placenta, the umbilical arteries branch radially to form chorionic arteries. Chorionic arteries, in turn, branch into cotyledon arteries. In the villi, these vessels eventually branch to form an extensive arterio-capillary-venous system, bringing the fetal blood extremely close to the maternal blood; but no intermingling of fetal and maternal blood occurs ("placental barrier"[7]).
Endothelin and prostanoids cause vasoconstriction in placental arteries, while nitric oxide vasodilation.[8] On the other hand, there is no neural vascular regulation, and catecholamines have only little effect.[8]
Functions
Nutrition
The perfusion of the intervillous spaces of the placenta with maternal blood allows the transfer of nutrients and oxygen from the mother to the fetus and the transfer of waste products and carbon dioxide back from the fetus to the maternal blood supply. Nutrient transfer to the fetus occurs via both active and passive transport. Active transport systems allow significantly different plasma concentrations of various large molecules to be maintained on the maternal and fetal sides of the placental barrier.[9]
Adverse pregnancy situations, such as those involving maternal diabetes, smoking or obesity, can increase or decrease levels of nutrient transporters in the placenta resulting in overgrowth or restricted growth of the fetus[citation needed].
Excretion
Waste products excreted from the fetus such as urea, uric acid and creatinine are transferred to the maternal blood by diffusion across the placenta.
Immunity
IgG antibodies can pass through the human placenta, thereby providing protection to the fetus in utero.[10]
Furthermore, the placenta functions as a selective maternal-fetal barrier against transmission of microbes to the fetus. However, insufficiency in this function may still cause mother-to-child transmission of infectious diseases.
Endocrine function
In humans, aside from serving as the conduit for oxygen and nutrients for fetus, the placenta secretes hormones (secreted by syncytial layer/syncytiotrophoblast of chorionic villi) that are important during pregnancy.
Hormones:
Human Chorionic Gonadotropin (hCG): The first placental hormone produced is hCG, which can be found in maternal blood and urine as early as the first missed menstrual period (shortly after implantation has occurred) through about the 100th day of pregnancy. This is the hormone analyzed by pregnancy test; a false-negative result from a pregnancy test may be obtained before or after this period. Women's blood serum will be completely negative for hCG by one to two weeks after birth. hCG testing is proof that all placental tissue is delivered. hCG is present only during pregnancy because it is secreted by the placenta, which is present only[11] during pregnancy. hCG also ensures that the corpus luteum continues to secrete progesterone and estrogen. Progesterone is very important during pregnancy because, when its secretion decreases, the endometrial lining will slough off and pregnancy will be lost. hCG suppresses the maternal immunologic response so that placenta is not rejected.
Human Placental Lactogen (hPL [Human Chorionic Somatomammotropin]): This hormone is lactogenic and growth-promoting properties. It promotes mammary gland growth in preparation for lactation in the mother. It also regulates maternal glucose, protein, and fat levels so that this is always available to the fetus.
Estrogen is referred to as the "hormone of women" because it stimulates the development of secondary female sex characteristics. It contributes to the woman's mammary gland development in preparation for lactation and stimulates uterine growth to accommodate growing fetus.
Progesterone is necessary to maintain endometrial lining of the uterus during pregnancy. This hormone prevents preterm labor by reducing myometrial contraction. Levels of progesterone are high during pregnancy.
Cloaking from immune system of mother
Further information: Immune tolerance in pregnancy
The placenta and fetus may be regarded as a foreign allograft inside the mother, and thus must evade from attack by the mother's immune system.
For this purpose, the placenta uses several mechanisms:
- It secretes Neurokinin B-containing phosphocholine molecules. This is the same mechanism used by parasitic nematodes to avoid detection by the immune system of their host.[12]
- There is presence of small lymphocytic suppressor cells in the fetus that inhibit maternal cytotoxic T cells by inhibiting the response to interleukin 2.[13]
However, the placental barrier is not the sole means to evade the immune system, as foreign fetal cells also persist in the maternal circulation, on the other side of the placental barrier.[14]
Other functions
The placenta also provides a reservoir of blood for the fetus, delivering blood to it in case of hypotension and vice versa, comparable to a capacitor.[15]
Birth
(examples at bottom reference premature infants: lower than 9-month birth weight.
Main article: Placental expulsion
Placental expulsion begins as a physiological separation from the wall of the uterus. The period from just after the fetus is expelled until just after the placenta is expelled is called the third stage of labor. The placenta is usually expelled within 15–30 minutes of the baby's being born. This may also be longer, relying on hormonal situ and psychological adjustment to delivery.
Placental expulsion can be managed actively, for example by giving oxytocin via intramuscular injection followed by cord traction to assist in delivering the placenta. As an alternative, it can be managed expectantly, allowing the placenta to be expelled without medical assistance. A Cochrane database study[16] suggests that blood loss and the risk of postpartum bleeding may be reduced in women offered active management of the third stage of labour (needs updating).
The "habit" is to cut the umbilical cord immediately after the baby is born, but there is no medical reason to do that; on the contrary, it seems that not cutting the cord helps the baby in his adaptation to extra uterine life, especially in preterm infants (Mercier, J.S. & Vohr, B.R. (2010).
Seven-month developmental outcomes of very low birth weight infants enrolled in a randomized controlled trial of delayed versus immediate cord clamping. Journal of Perinatology, 30(1):1.) How long the delay?
Read elsewhere: That the cord must be clamped until the beating stops: like an supremely venous intestine in appearance. No reference as to whether the upper comment is discussing immediate or very delayed oxygen/iron absorption.
Pathology
Main article: Placental disease
Numerous pathologies can affect the placenta.
- Placenta accreta (when the placenta implants too deeply, into actual muscle of uterine wall)
- Placenta praevia
- Placental abruption/abruptio placentae
Infections involving the placenta:
- Placentitis, such as the TORCH infections.
- Chorioamnionitis.
Cultural practices and beliefs
The placenta often plays an important role in various cultures, with many societies conducting rituals regarding its disposal. In the Western world, the placenta is most often incinerated.[17]
Some cultures bury the placenta for various reasons. The Māori of New Zealand traditionally bury the placenta from a newborn child to emphasize the relationship between humans and the earth.[18] Likewise, the Navajo bury the placenta and umbilical cord at a specially chosen site,[19] particularly if the baby dies during birth.[20] In Cambodia and Costa Rica, burial of the placenta is believed to protect and ensure the health of the baby and the mother.[21] If a mother dies in childbirth, the Aymara of Bolivia bury the placenta in a secret place so that the mother's spirit will not return to claim her baby's life.[22]
The placenta is believed by some communities to have power over the lives of the baby or its parents. The Kwakiutl of British Columbia bury girls' placentas to give the girl skill in digging clams, and expose boys' placentas to ravens to encourage future prophetic visions. In Turkey, the proper disposal of the placenta and umbilical cord is believed to promote devoutness in the child later in life. In Ukraine, Transylvania, and Japan, interaction with a disposed placenta is thought to influence the parents' future fertility. The Hmong bury the placenta under the central column of the house if it's a boy, and under the parent's bed if it's a girl - so that when the person dies the soul can go retrieve their first "clothing" and return to their ancestors to be reborn.
Several cultures believe the placenta to be or have been alive, often a relative of the baby. Nepalese think of the placenta as a friend of the baby; Malaysian Orang Asli regard it as the baby's older sibling. The Ibo of Nigeria consider the placenta the deceased twin of the baby, and conduct full funeral rites for it.[21] Native Hawaiians believe that the placenta is a part of the baby, and traditionally plant it with a tree that can then grow alongside the child.[17] Various cultures in Indonesia, such as Javanese, believe that the placenta has a spirit and needs to be buried outside the family house.
In some cultures, the placenta is eaten, a practice known as placentophagy. In some eastern cultures, such as China and Hong Kong, the dried placenta (紫河車) is sometimes used in preparations of traditional Chinese medicine.[23]
Additional images
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Fetus of about 8 weeks, enclosed in the amnion. Magnified a little over two diameters.
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Picture of freshly delivered placenta and umbilical cord wrapped around Kelly clamps
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Fresh human placenta
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Micrograph of a placental infection (CMV placentitis).
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Micrograph of CMV placentitis.
See also
References
- ^ Pough et al. 1992. Herpetology: Third Edition. Pearson Prentice Hall:Pearson Education, Inc., 2002.
- ^ Blackburn, D. G. and Flemming, A. F. (2011), Invasive implantation and intimate placental associations in a placentotrophic african lizard, Trachylepis ivensi (scincidae) Journal of Morphology. doi:10.1002/jmor.11011
- ^ Henry George Liddell, Robert Scott, "A Greek-English Lexicon", at Perseus
- ^ Definitions of placental- related terms.
- ^ Examination of the placenta
- ^ Placental Structure and Classification
- ^ Placental blood circulation
- ^ a b Kiserud, T.; Acharya, G. (2004). "The fetal circulation". Prenatal Diagnosis 24 (13): 1049–1059. doi:10.1002/pd.1062. PMID 15614842.
- ^ Wright, Caroline; Sibley, Colin P. (2011). "Placental Transfer in Health and Disease". In Helen Kay, Michael Nelson, and Yuping Wang. The Placenta: From Development to Disease. John Wiley and Sons. pp. 66. ISBN 978-1-4443-3366-4.
- ^ Simister, N.E., and Story, C.M. 1997. "Human placental Fc receptors and the transmission of antibodies from mother to fetus." Journal of Reproductive Immunology 37: 1-23
- ^ Pillitteri, Adele(2010). Maternal and Child Health Nursing(6th Edition[Philippine Edition]): Lippincott Williams & Wilkins
- ^ "Placenta 'fools body's defences'". BBC News. 10 November 2007. http://news.bbc.co.uk/1/hi/health/7081298.stm.
- ^ Clark DA, Chaput A, Tutton D (March 1986). "Active suppression of host-vs-graft reaction in pregnant mice. VII. Spontaneous abortion of allogeneic CBA/J x DBA/2 fetuses in the uterus of CBA/J mice correlates with deficient non-T suppressor cell activity". J. Immunol. 136 (5): 1668–75. PMID 2936806.
- ^ Williams Z, Zepf D, Longtine J, et al. (March 2008). "Foreign fetal cells persist in the maternal circulation". Fertil. Steril. 91 (6): 2593–5. doi:10.1016/j.fertnstert.2008.02.008. PMID 18384774.
- ^ Assad, R. S.; Lee, F. Y.; Hanley, F. L. (2001). "Placental compliance during fetal extracorporeal circulation". Journal of applied physiology (Bethesda, Md. : 1985) 90 (5): 1882–1886. PMID 11299282.
- ^ Prendiville, W. J.; Elbourne, D.; McDonald, S. J.; Begley, C. M. (2000). Active versus expectant management in the third stage of labour. In Begley, Cecily M. "Cochrane Database of Systematic Reviews". Cochrane Database of Systematic Reviews (3). doi:10.1002/14651858.CD000007.
- ^ a b "Why eat a placenta?". BBC. 18 April 2006. http://news.bbc.co.uk/2/hi/uk_news/magazine/4918290.stm. Retrieved 8 January 2008.
- ^ Metge, Joan. 2005. "Working in/Playing with three languages: English, Te Reo Maori, and Maori Bod Language." In Sites N.S vol. 2, No 2:83-90.
- ^ Francisco, Edna (3 December 2004). "Bridging the Cultural Divide in Medicine". Minority Scientists Network. http://sciencecareers.sciencemag.org/career_development/previous_issues/articles/3360/bridging_the_cultural_divide_in_medicine/. Retrieved 7 January 2008.
- ^ Shepardson, Mary (1978). "Changes in Navajo Mortuary Practices and Beliefs". American Indian Quarterly. University of Nebraska Press. JSTOR 0095182x.[dead link]
- ^ a b Buckley, Sarah J.. "Placenta Rituals and Folklore from around the World". Mothering. Archived from the original on 6 January 2008. http://web.archive.org/web/20080106075807/http://www.mothering.com/articles/pregnancy_birth/birth_preparation/amazing_placenta_side.html. Retrieved 7 January 2008.
- ^ Davenport, Ann (June 2005). "The Love Offer". Johns Hopkins Magazine. http://www.jhu.edu/~jhumag/0605web/ruminate.html. Retrieved 7 January 2008.
- ^ Falcao, Ronnie. "Medicinal Uses of the Placenta". http://www.gentlebirth.org/archives/eatplcnt.html. Retrieved 25 November 2008.
External links
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- Additional Human placenta photography
- The Placenta, gynob.com, with quotes from Williams Obstetrics, 18th Edition, F. Gary Cunningham, M.D., Paul C. MacDonald, M.D., Norman F. Grant, M.D., Appleton & Lange, Publishers.
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Translations:
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Placenta
Nederlands (Dutch)
moederkoek, zaadkoek (planten)
Français (French)
n. - placenta
Deutsch (German)
n. - Plazenta, Mutterkuchen
Ελληνική (Greek)
n. - (φυσιολ.) πλακούντας, ύστερο(ν)
Português (Portuguese)
n. - placenta (f)
Español (Spanish)
n. - placenta
Svenska (Swedish)
n. - moderkaka, placenta
中文（简体）(Chinese (Simplified))
胎盘, 胎座
中文（繁體）(Chinese (Traditional))
n. - 胎盤, 胎座
العربيه (Arabic)
(الاسم) المشيمه, السخد, غشاء الجنين الذي يخرج معه عند الولادة, جزء من سطح المبيض
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American Heritage Dictionary
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
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Britannica Concise Encyclopedia
Britannica Concise Encyclopedia. © 1994-2012 Encyclopædia Britannica, Inc. All rights reserved. Read more
Oxford Companion to the Body
The Oxford Companion to the Body. Copyright © 2001, 2003 by Oxford University Press. All rights reserved.
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Oxford Dictionary of English Folklore
A Dictionary of English Folklore. Copyright © 2000, 2003 by Oxford University Press. All rights reserved.
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Columbia Encyclopedia
The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2012, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/.
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Dictionary of Cultural Literacy: Health
The New Dictionary of Cultural Literacy, Third Edition Edited by E.D. Hirsch, Jr., Joseph F. Kett, and
James Trefil. Copyright © 2002 by Houghton Mifflin Company. Published by Houghton Mifflin. All rights reserved.
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Oxford Dictionary of Biochemistry
Oxford University Press. Oxford Dictionary of Biochemistry and Molecular Biology © 1997, 2000, 2006 All rights reserved.
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Saunders Veterinary Dictionary
Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved.
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Mosby's Dental Dictionary
Mosby's Dental Dictionary. Copyright © 2004 by Elsevier, Inc. All rights reserved.
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Random House Word Menu
© 2010 Write Brothers Inc. Word Menu is a registered trademark of the Estate of Stephen Glazier.
Write Brothers Inc.
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Wikipedia on Answers.com
This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article Placenta.
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