The umbilical cord in a full term infant contains:
High-Yield Explanation
Ans. a (Two arteries and one vein). (Ref. Human Embryology by JB Singh, 7th ed., p 54)UMBILICAL CORD# It attaches the fetus to the placenta; its length at full time, as a rule, is about equal to the length of the fetus, i.e., about 50 cm, but it may be greatly diminished or increased# Included in it are the body-stalk and the vitelline duct--the former containing the allantoic diverticulum and the umbilical vessels (two arteries and one vein), the latter forming the communication between the digestive tube and the yolk-sac. The body-stalk is the posterior segment of the embryonic area, and is attached to the chorion.# Running through its mesoderm are the two umbilical arteries and the two umbilical veins, together with the canal of the allantois--the last being lined by ectoderm.# Its dorsal surface is covered by the amnion, while its ventral surface is bounded by the extra-embryonic celom, and is in contact with the vitelline duct and yolk-sac.# The cord is covered by a layer of ectoderm which is continuous with that of the amnion, and its various constituents are enveloped by embryonic gelatinous tissue, jelly of Wharton. The vitelline vessels and duct, together with the right umbilical vein, undergo atrophy and disappear; and thus the cord, at birth, contains a pair of umbilical arteries and one (the left) umbilical vein.