Final answer:
The umbilical vein in fetal development becomes the ligamentum teres hepatis, which is the round ligament of the liver. It marks a transition from fetal to newborn circulation and serves as an internal landmark within the liver after birth.
Step-by-step explanation:
In fetal development, the umbilical vein becomes the round ligament of the liver, also known as the ligamentum teres hepatis. During embryogenesis, the primitive gut is formed through the embryonic folding process, which encompasses the development of various internal organs, including the liver. As the fetus matures, the previously functioning umbilical vein, which carries oxygenated blood from the placenta to the growing fetus, transforms into a fibrous remnant within the liver structure known as the round ligament of the liver.
This transformation is part of the body's adaptation from fetal to newborn circulation. The ligamentum teres hepatis doesn't carry blood anymore but serves as a landmark within the liver architecture, separating the right and left lobes of the liver anteriorly. It is one of several peritoneal folds and ligaments that stabilize the liver in the abdominal cavity.