Trophoblast

Notice - Mark Hill

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Human Blastocyst (day 5), trophoblast cells form the peripheral flattened epithelial layer of cells directly under the zona pellucida.

Introduction

(Greek, trophe = "nutrition" and -blast, a primordial cell) During early development the trophoblast cells have an important contribution to extraembryonic tissues (fetal placenta and membranes) and processes of early development (adplantation, implantation and endocrine support of pregnancy).

In humans, week 1 blastocyst formation the outer layer of cells (adjacent to the zona pellucida) form a flat squamous epithelial layer of cells, the trophoblast layer. Week 2 following blastocyst hatching the trophoblast layer is involved with initial adhesion to the uterine wall and subsequent implantation within the wall. During this period the trophoblast layer differentiates into two distinct layers (syncitiotrophoblast and cytotrophoblast).

Links: Blastocyst | Implantation | Week 2 | Week 3 | Placenta Development

Some Recent Findings

Angiogenic growth factors "Fourteen angiogenic growth factors were measured by multiplex growth factor analysis or ELISA in tissue culture supernatants from EVT and CTB from pregnancies at 8-10 and 12-14 weeks' gestation. Gestational age and cell type differences were observed. Extravillous trophoblast (EVT) and villous cytotrophoblast (CTB) are major producers of angiogenic growth factors that likely contribute to placental vascular development and spiral artery remodeling."

Trophoblast and Placental Villi

Early placental development cartoon showing trophoblast contribution to placental villi.

Legend

• SYN - syncytiotrophoblasts
• sCTB - subsyncytial cytotrophoblasts (this layer grows increasingly discontinuous in later trimesters)
• EVT - extravillous cytotrophoblasts (anchor the villous tree in the decidua)

References

Articles

<pubmed>19582159</pubmed>

Search PubMed

Search Pubmed: Trophoblast | syncitiotrophoblast | cytotrophoblast |

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Cite this page: Hill, M.A. (2024, May 18) Embryology Trophoblast. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Trophoblast

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G