The umbilical vein and umbilical arteries that make up the fetal umbilical cord carry blood between the mother and unborn child. Without this blood supply, the fetus would be unable to get nutrients from the mother or get rid of waste products.
The Purpose of the Umbilical Cord – Umbilical Cord Function
The umbilical cord is one of the most important things in an unborn baby's environment. The cord connects the fetal blood supply to the maternal blood supply. It carries oxygenated blood and nutrients from the mother, by way of the placenta, to the baby.
It also carries blood in the opposite direction, from the baby to the placenta. This blood has been emptied of nutrients and oxygen and now carries the fetus' waste products back to the mother's bloodstream where she can dispose of them through her system.
Umbilical Cord Structure – How the Umbilical Cord Looks
The umbilical cord looks like a long twisted white tube that attaches on one end to the baby's abdomen, where the belly button will be, and at the other end to the placenta.
Inside the cord, there are generally two arteries and one vein. The vein carries blood and nutrients to the baby from the placenta and the arteries carry blood from the fetus to the placenta. The two umbilical arteries wrap around the larger umbilical vein inside the cord. In most babies, the umbilical cord twists to the left, coiling like a phone cord. This twisting allows the cord to lengthen and shorten with the baby's movements.
Sometimes, only one umbilical artery is present, in a condition called single umbilical artery. This condition can indicate possible chromosomal problems, but many babies with single umbilical artery develop fine and are born with no apparent problems.
These blood vessels in the umbilical cord are protected by a gel-like substance called Wharton's jelly, which surrounds the vessels and allows the cord to handle being twisted, knotted or bent without being damaged.
Growth of the Umbilical Cord
At about four to six weeks post-conception, the umbilical cord begins to form. It grows longer and longer throughout the pregnancy until about 28 weeks, when it reaches its maximum length of about 22-24 inches.
In early development, the fetal intestines bulge out from the abdomen into the umbilical cord, but they return to the body by approximately eleven- twelve weeks. The cord elongates quickly after this has occurred.
The importance of the umbilical cord to fetal development cannot be understated. The unborn baby relies on the cord to provide and direct proper fetal blood circulation and allow the baby to grow and develop correctly. Umbilical cord problems and defects sometimes occur, and can range from minor to severe.
Sources:
Larsen, William J. Human Embryology. Churchill Livingstone. 2001
Marie Helen Beall, MD. Umbilical Cord Complications. eMedicine
 |
 |
 |
 |
 |
