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Note:There are normally 2 umbilical arteries and 1 umbilical vein. The umbilical vein carries oxygen-rich blood from the placenta to the embryo and is recognizable by its larger size and brighter red color.Label Key:1. placental vessels 2. umbilical vein 3. placenta 4. umbilical arteries | ||
All ages referenced to fertilization, not last menstrual period. |