primitive yolk sac

WordNet

1. used of preliterate or tribal or nonindustrial societies; "primitive societies"
2. a person who belongs to an early stage of civilization (同)primitive person
3. a mathematical expression from which another expression is derived
4. a word serving as the basis for inflected or derived forms; "`pick is the primitive from which `picket is derived"
5. of or created by one without formal training; simple or naive in style; "primitive art such as that by Grandma Moses is often colorful and striking" (同)naive
6. nutritive material of an ovum stored for the nutrition of an embryo (especially the yellow mass of a bird or reptile egg) (同)vitellus
7. a structure resembling a bag in an animal

PrepTutorEJDIC

1. 『原始の』,太古の / 原始的な,そぼくな;古風な,旧式な / 原始人
2. (卵の)黄身,卵黄
3. 小袋,のう(動植物の内部にあり,特に液を含んだもの)

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/07/31 13:00:40」(JST)

wiki en

[Wiki en表示]

Yolk sac
Human embryo of 3.6 mm.
Human embryo from thirty-one to thirty-four days
Details
Carnegie stage	5b
Days	9
Precursor	endoderm
Identifiers
Latin	vesicula umbilicalis; saccus vitellinus
MeSH	sac A10.615.284.981
TE	E5.7.1.0.0.0.4
FMA	87180
Anatomical terminology [edit on Wikidata]

The yolk sac is a membranous sac attached to an embryo, formed by cells of the hypoblast adjacent to the embryonic disk. This is alternatively called the umbilical vesicle by the Terminologia Embryologica (TE), though yolk sac is far more widely used. The yolk sac is important in early embryonic blood supply, and is incorporated into the primordial gut during the fourth week of development.

In humans

Contents in the cavity of the uterus seen at approximately 5 weeks of gestational age by obstetric ultrasonography.

Artificially colored, showing gestational sac, yolk sac and embryo (measuring 3 mm as the distance between the + signs).

The yolk sac is the first element seen in the gestational sac during pregnancy, usually at 3 days gestation. Identification of the gestational sac is a critical landmark in monitoring an early pregnancy, and can be reliably seen in human pregnancy using ultrasound.

The yolk sac is situated on the ventral aspect of the embryo; it is lined by extra-embryonic endoderm, outside of which is a layer of extra-embryonic mesenchyme, derived from the mesoderm.

Blood is conveyed to the wall of the yolk sac by the primitive aorta, and after circulating through a wide-meshed capillary plexus, is returned by the vitelline veins to the tubular heart of the embryo. This constitutes the vitelline circulation, and by means of it nutritive material is absorbed from the yolk sac and conveyed to the embryo.

At the end of the fourth week the yolk sac presents the appearance of a small pear-shaped opening (traditionally called the umbilical vesicle), into the digestive tube by a long narrow tube, the vitelline duct.

• Diagram showing earliest observed stage of human ovum.

• Diagram illustrating early formation of allantois and differentiation of body-stalk.

• Diagram showing later stage of allantoic development with commencing constriction of the yolk-sac.

• Diagram illustrating a later stage in the development of the umbilical cord.

The yolk sac can be seen in the afterbirth as a small, somewhat oval-shaped body whose diameter varies from 1 mm. to 5 mm.; it is situated between the amnion and the chorion and may lie on or at a varying distance from the placenta.

As a rule the duct undergoes complete obliteration during the seventh week, but in about two percent of cases its proximal part persists as a diverticulum from the small intestine, Meckel's diverticulum, which is situated about 60 cm proximal to the ileocecal valve, and may be attached by a fibrous cord to the abdominal wall at the umbilicus.

Sometimes a narrowing of the lumen of the ileum is seen opposite the site of attachment of the duct.

Histogenesis

The yolk sac starts forming during the second week of the embryonic development, at the same time of the shaping of the amniotic sac. The hypoblast starts proliferating laterally and descending. In the meantime Heuser's membrane, located on the opposite pole of the developing vesicle, starts its upward proliferation and meets the hypoblast.

Modifications

• Primary yolk sac: it is the vesicle constituted in the second week, its floor is represented by Heuser's membrane and its ceiling by the hypoblast. It is also known as the exocoelomic cavity.
• Secondary yolk sac: this structure is formed when the extraembryonic mesoderm separates to form the extraembryonic coelom; cells from the mesoderm pinch of an area of the yolk sac, and what remains is the secondary yolk sac.
• The final yolk sac: during the fourth week of development, during organogenesis, part of the yolk sac is surrounded by endoderm and incorporated into the embryo as the gut. The remaining part of the yolk sac is the final yolk sac.

Additional images

• Surface view of embryo of Hylobates concolor.

• Human embryo—length, 2 mm. Dorsal view, with the amnion laid open. X 30.

• Dorsum of human embryo, 2.11 mm. in length.

• Section through the embryo.

• Fetus of about eight weeks, enclosed in the amnion. Magnified a little over two diameters.

• Model of human embryo 1.3 mm. long.

• Section through ovum imbedded in the uterine decidua

• Human embryo about fifteen days old. Brain and heart represented from right side. Digestive tube and yolk sac in median section.

See also

• Yolk sac tumor

References

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

• 1. 卵巣胚細胞腫瘍：病理、臨床症状、および診断 ovarian germ cell neoplasms pathology clinical manifestations and diagnosis
• 2. 精巣腫瘍の解剖学および病理 anatomy and pathology of testicular tumors
• 3. 胎児および新生児における免疫細胞の発達 the development of immune cells in the fetus and neonate
• 4. BおよびTリンパ球の正常な発生 normal b and t lymphocyte development
• 5. 部位不明妊娠の超音波検査 ultrasonography of pregnancy of unknown location

English Journal

• Critical requirement of VEGF-C in transition to fetal erythropoiesis.

• Fang S1, Nurmi H1, Heinolainen K1, Chen S1, Salminen E1, Saharinen P1, Mikkola HK2, Alitalo K1.
• Blood.Blood.2016 Aug 4;128(5):710-20. doi: 10.1182/blood-2015-12-687970. Epub 2016 Jun 24.
• Vascular endothelial growth factor C (VEGF-C) is a major driver of lymphangiogenesis in embryos and adults. Vegfc gene deletion in mouse embryos results in failure of lymphangiogenesis, fluid accumulation in tissues, and lethality. The VEGF-C receptors VEGFR3 and VEGFR2 are required for embryonic bl
• PMID 27343251

• Analysis of extraembryonic mesodermal structure formation in the absence of morphological primitive streak.

• Jin JZ1, Zhu Y1, Warner D1, Ding J1.
• Development, growth & differentiation.Dev Growth Differ.2016 Aug;58(6):522-9. doi: 10.1111/dgd.12294. Epub 2016 Jun 8.
• During mouse gastrulation, the primitive streak is formed on the posterior side of the embryo. Cells migrate out of the primitive streak to form the future mesoderm and endoderm. Fate mapping studies revealed a group of cell migrate through the proximal end of the primitive streak and give rise to t
• PMID 27273137

• Resolving early mesoderm diversification through single-cell expression profiling.

• Scialdone A1,2, Tanaka Y3,4, Jawaid W3,4, Moignard V3,4, Wilson NK3,4, Macaulay IC2, Marioni JC1,2,5, Göttgens B3,4.
• Nature.Nature.2016 Jul 6;535(7611):289-93. doi: 10.1038/nature18633.
• In mammals, specification of the three major germ layers occurs during gastrulation, when cells ingressing through the primitive streak differentiate into the precursor cells of major organ systems. However, the molecular mechanisms underlying this process remain unclear, as numbers of gastrulating
• PMID 27383781

Japanese Journal

• Erythropoietin Gene Expression: Developmental-Stage Specificity, Cell-Type Specificity, and Hypoxia Inducibility

• Suzuki Norio
• The Tohoku Journal of Experimental Medicine 235(3), 233-240, 2015
• … The first Epo-producing cells emerge in the neural crest and neuroepithelium of mid-stage embryos and support primitive erythropoiesis in the yolk sac. …
• NAID 130004822447

• The origin of the first blood cell

• YAMADA Yoshihiro
• Aino journal 9, 27-29, 2010
• … In mouse development, the first blood cell activity appears in the yolk sac at E7.5(embryonic day 7.5). … However,this blood cell activity (primitive hematopoiesis)is restricted to red blood cells (primitive erythrocytes). …
• NAID 110008731157

• 難治性小児悪性固形腫瘍に対するチオテパ+ブスルファンまたはチオテパ+メルファランによる大量化学療法の検討

• 大嶋 宏一,菊地 陽,望月 慎史,外山 大輔,内坂 直樹,北野 良博,内田 広夫,西本 博,栗原 淳,野澤 久美子,小熊 栄二,岸本 宏志,花田 良二
• 小児がん : 小児悪性腫瘍研究会記録 45(3), 256-263, 2008-09-25
• チオテパ大量療法を行った難治性小児悪性固形腫瘍21例について検討した.移植適応を,再発のために経過中に大量化学療法の適応を決定した救済移植群と,治療当初からの計画的移植群とに分けた.対象疾患の悪性度が高いにも関わらず,計画的移植群では再発後死亡はみられていない.一方,救済移植群では移植時の状態が寛解以外の症例は全例が移植後再発し,再発後には1例を除いて全員が原病死した.再発固形腫瘍では移植前に寛解 …
• NAID 110007170703

Related Links

• 卵黄嚢 - Wikipedia

ここでの造血活動は卵黄嚢造血と呼ばれ、胎生10日～2ヶ月の間の造血が行われる。 一次卵黄嚢 primary yolk sac（原始卵黄嚢 primitive yolk sac）は縮んで消滅するが、 二次卵黄嚢 secondary yolk sacもできる。 最終的に、二次卵黄嚢の背方部は原腸 ...

• Yolk sac - Wikipedia, the free encyclopedia

The yolk sac is a membranous sac attached to an embryo, providing early nourishment in the form of yolk in bony fishes, sharks, reptiles, birds, and primitive mammals. It functions as the developmental circulatory system of the human embryo, ...

Related Pictures

---

★リンクテーブル★

リンク元	「原始卵黄嚢」
関連記事	「sac」「yolk」「primitive」「yolk sac」

「原始卵黄嚢」

　　[★]

英

primitive yolk sac

関

胚外体腔

「sac」

　　[★]

• n.

• 嚢

関

bursa、bursae、cysterna、pouch

　 　

「yolk」

　　[★]

• n.

• 卵黄

関

egg yolk、vitelline、vitellus

　 　

「primitive」

　　[★]

• adj.

• 原始的な

関

primitively

　 　 　 　 　 　

「yolk sac」

　　[★] 卵黄嚢

関

umbilical vesicle