Chorionic (plate) vessels, also fetal surface vessels are

blood vessels Blood vessels are the tubular structures of a circulatory system that transport blood throughout many animals’ bodies. Blood vessels transport blood cells, nutrients, and oxygen to most of the tissues of a body. They also take waste an ...

, including both

arteries An artery () is a blood vessel in humans and most other animals that takes oxygenated blood away from the heart in the systemic circulation to one or more parts of the body. Exceptions that carry deoxygenated blood are the pulmonary arteries in ...

and

veins Veins () are blood vessels in the circulatory system of humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are those of the pulmonary and fetal c ...

, that carry blood through the

chorion The chorion is the outermost fetal membrane around the embryo in mammals, birds and reptiles (amniotes). It is also present around the embryo of other animals, like insects and molluscs. Structure In humans and other therian mammals, the cho ...

in the fetoplacental circulation. Chorionic arteries branch off the

umbilical artery The umbilical artery is a paired artery (with one for each half of the body) that is found in the abdominal and pelvic regions. In the fetus, it extends into the umbilical cord. Structure Development The umbilical arteries supply systemic arter ...

, and supply the capillaries of the

chorionic villi Chorionic villi are Wiktionary:villus, villi that sprout from the chorion to provide maximal contact area with maternal blood. They are an essential element in pregnancy from a histology, histomorphologic perspective, and are, by definition, a pr ...

. Increased vasocontractility of chorionic arteries may contribute to

preeclampsia Pre-eclampsia is a multi-system disorder specific to pregnancy, characterized by the new onset of high blood pressure and often a significant amount of protein in the urine or by the new onset of high blood pressure along with significant end- ...

References

Embryology of cardiovascular system {{circulatory-stub