Final answer:
The umbilical cord contains two umbilical arteries and one umbilical vein, connecting the fetus to the placenta. Post-birth, the cord is clamped, cut, and its stub later forms the navel as the vessels atrophy and become ligaments, with the arteries still functioning to supply blood to parts of the bladder.
Step-by-step explanation:
The umbilical cord is a long, narrow conduit that plays a crucial role during pregnancy, connecting the developing fetus to the placenta. It consists of two umbilical arteries and one umbilical vein. The arteries are responsible for carrying fetal blood, low in oxygen and high in waste products, to the placenta where exchange with the maternal blood occurs. In contrast, the umbilical vein carries oxygenated and nutrient-rich blood from the placenta back to the fetal heart, providing the necessary components for continued development.
After birth, the umbilical cord is usually clamped and cut, leaving behind a stub that eventually dries out, shrivels, and falls off to become the navel. This transformation from a vital lifeline to a remnant happens as the umbilical blood vessels collapse, a process that would naturally take place through the constriction of vessels due to Wharton's jelly reaction to cooler temperatures outside the mother's body if medical intervention was not available.
Eventually, the collapsed vessels of the umbilical cord atrophy and become fibrotic remnants that exist in the mature circulatory system as various ligaments, while the proximal sections of the two umbilical arteries remain functional and serve to supply blood to the upper part of the bladder.