Umbilical cord

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Definitions

  • 1a : a cord arising from the navel that connects the fetus with the placenta and through which respiratory gases, nutrients, and wastes pass
b : yolk stalk
  • 2: a tethering or supply line (as for an astronaut outside a spacecraft or a diver underwater)
  • 3: a necessary, supportive, or nurturing link or connection

Description

In placental mammals, the umbilical cord (also called the birth cord or funiculus umbilicalis) is a conduit between the developing embryo or fetus and the placenta. During prenatal development, the umbilical cord is physiologically and genetically part of the fetus and (in humans) normally contains two arteries (the umbilical arteries) and one vein (the umbilical vein), buried within Wharton's jelly. The umbilical vein supplies the fetus with oxygenated, nutrient-rich blood from the placenta. Conversely, the fetal heart pumps deoxygenated, nutrient-depleted blood through the umbilical arteries back to the placenta.[1]

In some animals, the mother will gnaw through the cord, thus separating the placenta from the offspring. It (along with the placenta) is often eaten by the mother, to provide nourishment and to dispose of tissues that would otherwise attract scavengers or predators. In chimpanzees, the mother focuses no attention on umbilical severance, instead nursing her baby with cord, placenta, and all, until the cord dries and separates within a day of birth, at which time the cord is discarded. (This was first documented by zoologists in the wild in 1974.

The term "umbilical cord" or just "umbilical" has also come to be used for other cords with similar functions, such as the hose connecting a surface-supplied diver to his surface supply of air and/or heating, or a space-suited astronaut to his spacecraft. Engineers sometimes use the term to describe a complex or critical cable connecting a component, especially when composed of bundles of conductors of different colors, thickness and types, terminating in a single multi-contact disconnect.