Maternity Nursing Q 373
The normal umbilical cord is composed of:
A. 2 arteries and 1 vein
B. 2 veins and 1 artery
C. 2 arteries and 2 veins
D. None of the above
Correct Answer: A. 2 arteries and 1 vein
Three vessels comprise the umbilical cord: two umbilical arteries and one umbilical vein. The umbilical cord is a soft, tortuous cord with a smooth outer covering of amnion. It extends from the umbilicus of the fetus to the center of the placenta. Its length ranges from 50 cm to 60 cm, with a diameter of about 1 cm.[6] The umbilical cord is composed of a gelatinous ground substance called Wharton’s jelly or substantia gelatinea funiculi umbilicalis.
Option B: The umbilical arteries carry deoxygenated blood from fetal circulation to the placenta. The two umbilical arteries converge together about at 5 mm from the insertion of the cord, forming a type of vascular connection called the Hyrtl’s anastomosis. The primary function of Hartl’s anastomosis is to equalize blood flow and pressure between the umbilical and placental arteries.
Option C: The two umbilical arteries arise from the internal iliac arteries of the fetus and enter the umbilical cord before further branching at the level of the placenta. At the placental level, each umbilical artery bifurcates into smaller arterioles that continue to branch further to distribute blood to the chorionic villi. The capillaries of the villi fuse to form venules that converge to form the umbilical vein. The umbilical vein carries oxygenated blood and nutrients from the mother to the fetus.
Option D: The umbilical cord is considered both the physical and emotional attachment between mother and fetus. This structure allows for the transfer of oxygen and nutrients from the maternal circulation into fetal circulation while simultaneously removing waste products from fetal circulation to be eliminated maternally.