How many umbilical veins are present, and what is its function?

The correct answer highlights that there is one umbilical vein, and its primary function is to bring oxygenated blood to the fetus from the placenta. This is a critical aspect of fetal circulation. The umbilical vein carries nutrient-rich and oxygen-rich blood received from the placenta, which is vital for the developing fetus as it relies on this supply for growth and development.

In fetal circulation, the single umbilical vein is responsible for transporting the oxygen and nutrients necessary for the fetus, while there are two umbilical arteries that return deoxygenated blood from the fetus back to the placenta for oxygenation. This unique arrangement allows for efficient gas and nutrient exchange between the mother and fetus, which is essential for sustaining life during gestation.