chorionic villi

Definition : Chorionic villi are villi that sprout from the chorion to provide maximal contact area with maternal blood.

Branches of the umbilical arteries carry embryonic blood to the villi. After circulating through the capillaries of the villi, blood returns to the embryo through the umbilical vein. Thus, villi are part of the border between maternal and fetal blood during pregnancy.

Elements

The bulk of the villi consist of connective tissues that contain blood vessels. Most of the cells in the connective tissue core of the villi are fibroblasts. Macrophages known as Hofbauer cells are also present.

Images

 Blood cells in early chorionic villi

• https://twitter.com/a_sleeping_dog/status/809273540557959168

Pathology

 villitis

• villitis of unknown etiology (VUE)

See also

 placenta / Placenta