Syncytiotrophoblast
Primary chorionic villi. Diagrammatic.
Secondary chorionic villi. Diagrammatic.
Gray's	subject #6 47
Carnegie stage	5a
Days	8
MeSH	Syncytiotrophoblasts

Syncytiotrophoblasts are multinucleated cells found in the placenta of embryos.

They are the outer syncytial layer of the trophoblasts and actively invade the uterine wall.

They form the outermost fetal component of the placenta (also known as 'syntrophoblast') and massively increase the surface area available for nutrient exchange between the mother and the fetus.

Cells from the syncytiotrophoblast secrete progesterone in addition to human chorionic gonadotropin (hCG); the latter prevents degeneration of the corpus luteum. Progesterone serves to maintain the integrity of the uterine lining, and until the syncytiotrophoblast is mature enough to secrete enough progesterone (in the fourth month of embryonic development), it is aided by the corpus luteum graviditatis. ^[1]

Contents 1 Additional images 2 See also 3 References 4 External links

[edit] Additional images

Section through embryonic area of Vespertilio murinus to show the formation of the amniotic cavity.

[edit] See also

• Syncytium
• Cytotrophoblast

[edit] References

[edit] External links

• Histology at BU 19908loa - "Female Reproductive System: placental villi"
• Nature (Journal) Diagram
• Musicki B, Pepe G, Albrecht E (1997). "Functional differentiation of placental syncytiotrophoblasts during baboon pregnancy: developmental expression of chorionic somatomammotropin messenger ribonucleic acid and protein levels.". J Clin Endocrinol Metab 82 (12): 4105–10. doi:10.1210/jc.82.12.4105. PMID 9398722.  Article
• Diagram at McGill
• Syncytiotrophoblast at eMedicine Dictionary

v • d • e Developmental biology > Human embryogenesis (development of embryo) and development of fetus First three weeks Week 1 Fertilization · Egg activation · Zygote · Cleavage · Morula · Blastula (Blastomere) · Blastocyst · Inner cell mass Week 2 (Bilaminar) Hypoblast · Epiblast Week 3 (Trilaminar) Germ layers Archenteron/Primitive streak (Primitive pit, Primitive knot/Blastopore, Primitive groove) · Gastrula/Gastrulation · Regional specification Ectoderm Surface ectoderm · Neuroectoderm · Somatopleure · Neurulation · Neural crest Endoderm Splanchnopleure Mesoderm Chorda- · Paraxial (Somite/Somitomere/Sclerotome/Myotome/Dermatome) · Intermediate · Lateral plate (Intraembryonic coelom, Splanchnopleure/Somatopleure) Extraembryonic/ uterus Trophoblast (Cytotrophoblast, Syncytiotrophoblast) Blastocoele · Yolk sack/exocoelomic cavity · Heuser's membrane · Extraembryonic coelom · Vitelline duct Umbilical cord (Umbilical artery, Umbilical vein, Wharton's jelly) · Allantois Placenta · Decidua (Decidual cells) · Chorionic villi/Intervillous space · Gestational sac (Amnion/Amniotic sac/Amniotic cavity, Chorion) Histogenesis Programmed cell death (Apoptosis) · Stem cells · Germ line development Organogenesis Limb development: Limb bud · Apical ectodermal ridge/AER other structures: Eye development · Cutaneous structure development · Heart development · Development of the urinary and reproductive organs (Some dates are approximate—see Carnegie stages and a timeline.)

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