How does the body stalk become the umbilical cord?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

human fetus; prenatal development — prenatal development An ultrasound image of a human fetus.

The body stalk transforms into the umbilical cord through a process of folding and integration as the embryo develops its cylindrical shape.

As the ventral body wall closes, the yolk stalk and the allantois—along with their associated mesodermal sheaths and blood vessels—are brought together. This collection of structures is then enclosed by a wrapping of amnion. This cylindrical formation connects the embryo to the placenta, serving as a physiological lifeline that facilitates the exchange of nutrients, oxygen, and waste products between the fetus and the mother throughout the pregnancy.12