File:Placenta anchoring villi.jpg
Placenta_anchoring_villi.jpg (600 × 450 pixels, file size: 167 KB, MIME type: image/jpeg)
Placenta Anchoring Villi
Histological image showing the junctional region between the maternal decidua (left) and the embryonic placental villi (right).
- In week 2, the trophoblast shell cells proliferate and form a syncitiotrophoblast and cytotrophoblast layer around he conceptus.
- Syncitiotrophoblast cells migrate into the uterine wall, forming maternal blood-filled spaces (lacunae).
Placentation begins once the conceptus begins to implant in the uterine wall and the placenta will have both a fetal and a maternal component. The fetal component begins as villi form. The fetal chorion will form two regions: smooth chorion (chorion laeve) and villous chorion (chorion frondosum).
The maternal component is formed by the decidualization of the endometrium.
- Fibrinoid layer (Nitabuch's layer) is formed at maternal/fetal interface during placentation and is thought to act to prevent excessively deep conceptus implantation.
- Fibrin-type fibrinoid - maternal blood-clot product)
- Matrix-type fibrinoid - secreted by invasive extravillous trophoblast cells
Image Source: UNSW Embryology, no reproduction without permission.
Click on a date/time to view the file as it appeared at that time.
|current||14:37, 3 August 2009||600 × 450 (167 KB)||MarkHill||Placenta anchoring villi Histological image showing the junctional region between the trophoblast shell of the conceptus and the maternal decidua. In week 2, the trophoblast shell cells proliferate and form a syncitiotrophoblast and cytotrophoblast lay|