Above is an illustration of an umbilical cord. What is the structure labeled X?

If a baby needed emergency medication in the delivery room, you would give the medication through an

If a baby needed monitoring of blood oxygen, carbon dioxide, and pH levels, you would obtain blood samples from an

An umbilical venous catheter should be left in place until a baby is well.

If a constant infusion is to be given through an umbilical arterial catheter, an infusion pump must be used.

Umbilical venous catheters are most appropriately used for

You are inserting an umbilical arterial catheter in a baby. The baby's toes on his right foot suddenly turn white. What should be done?