Talk:BGDA Practical Placenta - Villi Development

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Human Villi Timeline

The placental vill development data below is based upon a recent immunochemistry confocal laser scanning microscope (CLSM) study.

Note that the paper uses clinical gestational age (GA) from last menstrual period (LMP) and has been corrected for post-conception (fertilization) age, approximately 14 days later.

Fertilization Age (weeks)	Gestational Age (weeks)	Vessel Lumen Diameter (range in microns, µm)	Features
3 to 4	5 and 6	10 - 15	a complex network of cords and vessels with redundant connections network comprises mainly cords, already connected together vessels and cords are connected to each other without any interruptions chorionic villus dominated by this network of vascular elements vessels and cords are located centrally as well as peripherally and as a consequence contact the overlying trophoblastic layer
5 to 6	7 and 8	10 - 26	villi dominated by capillary network of vessels and cords capillary network contains more vessels than cords
7 to 8	9 and 10	60 - 75 two central vessels 26 - 34 capillary network	villi have two large centrally located vessels surrounded by and connected to a peripheral capillary network capillary network contains vessels with a lumen in tight contact with overlying trophoblastic layer villous projections also contain blind ending capillary sprouts
9 to 10	11 and 12	70 - 90 two central vessels 26 - 34 capillary network	immature intermediate villi characterized by two large vessels surrounded by a capillary network capillary network has few cords blind ending capillary sprouts off the capillary network