Umbilical cord (40X)

This is a cross section of the umbilical cord. The three round structures in the middle are blood vessels. The two smallest ones are the umbilical arteries and the largest is the umbilical vein. As you might notice, the wall of the vein is much thicker than in other veins found throughout the body. The material surrounding the vessels is so-called mucoid connective tissue, better known as Wharton's jelly.