What is the thick myxomatous substance surrounding the umbilical vessels called?

The thick myxomatous substance that surrounds the umbilical vessels is known as Wharton's Jelly. This gelatinous tissue serves several important functions during pregnancy. It provides cushioning and support to the umbilical cord, protecting the vessels from compression or injury during the movements of pregnancy. Wharton's Jelly allows for flexibility, helping to ensure an unobstructed flow of blood between the placenta and the fetus.

Chorion, while an important membrane that contributes to the formation of the placenta, does not provide the specific protective functions associated with the umbilical cord vessels. Amniotic fluid is the fluid within the amniotic sac that surrounds and protects the developing fetus, whereas Vernix Caseosa is a cheese-like substance that covers the skin of the fetus, providing insulation and protection during development. Each of these substances plays distinct roles, but Wharton's Jelly specifically refers to the protective jelly surrounding the umbilical vessels.