Vein: Ductus venosus
Fetal circulation. The ductus venosus (red) connects the umbilical vein to the inferior vena cava.
The liver and the veins in connection with it, of a human embryo, twenty-four or twenty-five days old, as seen from the ventral surface.
Gray's	subject #139 540
Source	umbilical vein
Drains to	inferior vena cava
Artery	ductus arteriosus

In the fetus, the ductus venosus shunts a significant majority (80%) of the blood flow of the umbilical vein directly to the inferior vena cava. Thus, it allows oxygenated blood from the placenta to bypass the liver. In conjunction with the other fetal shunts, the foramen ovale and ductus arteriosus, it plays a critical role in preferentially shunting oxygenated blood to the fetal brain.

The ductus venosus is open at the time of the birth and is the reason why umbilical vein catheterization works. Ductus venosus naturally closes during the first week of life in most full-term neonates; however, it may take much longer to close in pre-term neonates. Functional closure occurs within minutes of birth. Structural closure in term babies occurs within 3 to 7 days.

After it closes, the remnant is known as ligamentum venosum.

If the ductus venosus fails to occlude after birth, the individual is said to have an intrahepatic portosystemic shunt (PSS). This condition is hereditary in some dog breeds (e.g. Irish Wolfhound).

[edit] See also

• Ligamentum venosum

[edit] External links

• 678101050 at GPnotebook - Ductus venosus (embryology)

This cardiovascular system article is a stub. You can help Wikipedia by expanding it. v • d • e