Umbilical Cord - definition and function
What is Umbilical Cord
The entwinement of the two umbilical arteries, one umbilical VEIN, and nerves that extend from the PLACENTA to the developing FETUS during PREGNANCY. The length of the umbilical cord varies according to numerous factors. The flow of BLOOD through the umbilical arteries and vein holds the umbilical cord relatively rigid. A thick gelatinous coating, called Wharton’s jelly, surrounds the umbilical cord to protect it as it floats in the AMNIOTIC FLUID.
Function of Umbilical Cord
The umbilical cord carries nourishment from the mother to the fetus and metabolic waste from the fetus to the mother via the blood circulation. The umbilical cord enters the fetus in the center of its abdomen. The umbilical arteries carry blood from the fetus to the placenta, which delivers oxygen and NUTRIENTS to the blood. The umbilical vein then carries the oxygenated blood back to the fetus.
Umbilical Cord and Childbirth
The third stage of childbirth is delivery of the placenta, often called the afterbirth. When the woman delivers the umbilical cord the doctor or midwife clamps it in two places, cuts between the clamps, and seals the end attached to the baby with a plastic clip. Within two to three weeks the stump of the umbilical cord shrivels, hardens, and falls off. In its place remains the SCAR that forms to close off the umbilical portal into the infant’s body, the umbilicus or navel (commonly called the belly button). The remnants of the umbilical arteries and umbilical vein become ligaments within the abdomen.
For further discussion of the umbilical cord within the context of the structures and functions of reproduction and sexuality, please see the overview section “The Reproductive System.”
See also ARTERY; BLOOD STEM CELLS; NERVE.
