Final answer:
The merging of the vitelline and umbilical vein forms the ductus venosus, which is a temporary blood vessel that allows oxygenated blood from the placenta to bypass the fetal liver and go directly to the fetal heart. Eventually, the ductus venosus closes and degenerates to become the ligamentum venosum beneath the liver.
Step-by-step explanation:
The merging of the vitelline and umbilical vein forms the ductus venosus. The ductus venosus is a temporary blood vessel that allows much of the freshly oxygenated blood from the placenta to bypass the fetal liver and go directly to the fetal heart. Eventually, the ductus venosus closes and degenerates to become the ligamentum venosum beneath the liver.
merging of the vitelline and umbilical vein forms the ductus venosus, which is a temporary blood vessel that allows oxygenated blood from the placenta to bypass the fetal liver and go directly to the fetal heart. Eventually, the ductus venosus closes and degenerates to become the ligamentum venosum beneath the liver.