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505:. The amnios consists of two layers:one is the granular layer, continued upon the inner or foetal surface of the allantois, and thence upon the umbilical cord; the other is the smooth outer layer, continued upon the outer or chorional surface of the allantois, and thence upon the inner surface of the chorion."
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In the human embryo, the earliest stages of the formation of the amnion have not been observed; in the youngest embryo that has been studied the amnion was already present as a closed sac, and appears in the inner cell-mass as a cavity. This cavity is roofed in by a single stratum of flattened,
356:ἀμνίον : amníon, 'little lamb', diminutive of ἀμνός : amnós, 'lamb'. It is cognate with the English verb 'yean', bring forth young (usually lambs). However, this etymology is perhaps incorrect as the term may actually refer to an ancient Greek goddess of childbirth worshipped in
407:
The amniotic fluid allows the free movements of the fetus during the later stages of pregnancy, and also protects it by diminishing the risk of injury from without. It contains less than two percent solids, consisting of urea and other extractives, inorganic salts, a small amount of
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400:) begins to accumulate within it. This fluid increases in quantity and causes the amnion to expand and ultimately to adhere to the chorion's inner surface, so that the extra-embryonic part of the
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is collected and under aseptic conditions, the amniotic membrane is separated and packaged and sold commercially. In valid commercial products to prevent transmission of viral infections such as
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is obliterated. The amniotic fluid increases in quantity up to the sixth or seventh month of pregnancy, after which it diminishes somewhat; at the end of pregnancy it amounts to about one liter.
529:, the donor's blood (mother) is tested. Products usually pass the sterility and endotoxin test in accordance with the rules of the Food and Drug Administration of the country of manufacture.
416:. That some of the liquor amnii is swallowed by the fetus is proved by the fact that epidermal debris and hairs have been found among the contents of the fetal alimentary canal.
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After the fusion of the edges of the amniotic fold, the two layers of the fold become completely separated, the inner forming the amnion, the outer the false amnion or
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end and sides of the embryo, and gradually rising, its different parts meet and fuse over the dorsal aspect of the embryo, and enclose a cavity, the
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Frech, T. M., et al. (2019). "Amniotic membrane dressings: an effective therapy for SSc-related wounds." Rheumatology (Oxford) 58(4): 734-736.
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The space between the amnion and the serosa constitutes the extra-embryonic celom, and for a time communicates with the embryonic celom.
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Extra-amniotic pregnancy is a rare condition that results from a rupture of the amnion, leading to development of the fetus within the
632:
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466:. This kind of amnion is known as pleuroamnion (formed by folding), as opposed to schyzoamnion (formed by delamination).
550:(ruptured at the margin at the left in the image), which consists of the amnion (inner layer) and chorion (outer layer)
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970: – Histology Learning System at Boston University - "Female Reproductive System: placenta, chorionic plate"
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When first formed, the amnion is in contact with the body of the embryo, but about the fourth or fifth week
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The amniotic membrane is used as a biological dressing to heal incurable wounds. For this purpose, the
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This, the amniotic fold, first makes its appearance at the cephalic extremity, and subsequently at the
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908:, Cuv.), with remarks on the value of placentary characters in the classification of the mammalia"
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that provides a protective environment for the developing embryo. The amnion, along with the
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Diagram of a transverse section, showing the mode of formation of the amnion in the chick.
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At the point of constriction where the primitive digestive tube of the embryo joins the
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Knowledge articles incorporating text from the 20th edition of Gray's
Anatomy (1918)
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and amnios, as to prevent any part of the amnios attaining the inner surface of the
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Human embryo—length, 2 mm. Dorsal view, with the amnion laid open. X 30.
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Innermost membranous sac that surrounds and protects a developing embryo
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By Luís Flávio Gonçalves, MD, Philippe Jeanty, MD, PhD. 1999-09-26-18
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and is connected by the body-stalk with the mesodermal lining of the
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are born inside of the amnion; the mother cuts it open and eats it.
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Sectional plan of the gravid uterus in the third and fourth month.
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a reflection or folding upward of the somatopleure takes place.
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795:"Treatment of second-degree burns with amniotic membranes"
373:, and its floor consists of the prismatic ectoderm of the
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Human embryo of about fourteen days, with yolk-sac.
377:. Outside the amniotic ectoderm is a thin layer of
259:, which causes the amnion to expand and become the
56:. Unsourced material may be challenged and removed.
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836:"The strange histories of some anatomical terms"
287:, the protective sac is enclosed in a shell. In
142:Chicken egg with amnion surrounding the embryo
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448:the amnion develops in the following manner:
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332:on the outer side and the extra-embryonic
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116:Learn how and when to remove this message
883:TheFetus.net > Amniotic band syndrome
626:Model of human embryo 1.3 mm. long.
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381:, which is continuous with that of the
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766:This article incorporates text in the
312:, which includes reptiles, birds, and
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19:For the fictional alien species, see
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255:when they first form. It fills with
154:Human fetus, enclosed in the amnion.
54:adding citations to reliable sources
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1014:Membranes of the fetus and embryo
979:The Foeto-Amnio-Placental complex
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650:Scheme of placental circulation.
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352:has been assumed to derive from
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302:The amnion is a feature of the
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324:lack the amnion and thus are
602:Human embryo of 2.6 mm.
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774:of the 20th edition of
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590:Section through the embryo.
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562:Surface view of embryo of
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968:Histology image: 19903loa
852:10.1017/S0025727300024200
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1044:Intermediate trophoblast
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360:on the island of Crete
348:Traditionally, the term
546:Placenta with attached
275:protect the embryo. In
933:10.1098/rstl.1857.0017
369:ectodermal cells, the
295:, it is enclosed in a
219:Anatomical terminology
730:, 6 maternal part of
426:extraembryonic coelom
420:Clinical significance
50:improve this article
1171:Reichert's membrane
1039:Syncytiotrophoblast
924:1857RSPT..147..347O
834:Singer, C. (1959).
793:Pigeon, J. (1960).
702:Opened uterus with
340:on the inner side.
1072:Intervillous space
888:2017-11-28 at the
564:Hylobates concolor
21:Amnion (Gap Cycle)
1244:Biological matter
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1166:Heuser's membrane
902:Owen, R. (1857).
533:Additional images
519:cesarean delivery
371:amniotic ectoderm
293:placental mammals
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48:Please help
43:verification
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1133:Circulatory
1029:Trophoblast
918:: 347–353.
736:endometrium
676:macrophages
509:Application
444:, and many
338:trophoblast
165:Identifiers
1234:Embryology
1218:Categories
1161:Blastocoel
846:(1): 1–7.
756:References
326:anamniotes
318:Amphibians
304:vertebrate
289:marsupials
285:monotremes
176:amniosinas
76:newspapers
1051:Allantois
840:Med. Hist
720:allantois
708:umbilicus
527:hepatitis
495:allantois
491:elephants
364:In humans
344:Etymology
273:allantois
106:June 2021
1140:Placenta
886:Archived
870:13632203
821:13735672
744:See also
732:placenta
728:hematoma
724:yolk sac
682:stained
680:meconium
515:placenta
503:placenta
453:yolk sac
438:reptiles
379:mesoderm
334:ectoderm
330:mesoderm
281:reptiles
271:and the
269:yolk sac
65:"Amnion"
1208:Anatomy
1145:Chorion
1056:Decidua
920:Bibcode
861:1034442
812:1938392
772:page 56
716:chorion
499:chorion
446:mammals
410:protein
387:chorion
358:Amnisos
314:mammals
309:Amniota
265:chorion
253:embryos
245:amnions
188:D000650
160:Details
90:scholar
1194:Portal
1087:cavity
1077:Amnion
1021:Embryo
974:McGill
942:108622
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780:(1918)
471:serosa
460:caudal
402:coelom
350:amnion
306:clade
297:uterus
267:, the
237:amnion
131:Amnion
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1154:Other
1099:Fetus
938:JSTOR
770:from
442:birds
414:sugar
277:birds
249:amnia
223:[
212:80223
171:Latin
97:JSTOR
83:books
866:PMID
817:PMID
722:, 4
710:, 2
525:and
484:dogs
482:and
480:Cats
322:fish
320:and
291:and
283:and
235:The
183:MeSH
69:news
1082:sac
928:doi
916:147
856:PMC
848:doi
807:PMC
704:cat
678:in
523:HIV
517:in
489:In
436:In
336:or
247:or
241:pl.
207:FMA
52:by
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