Question

Blood flowing in the umbilical cord of the mammalian embryo
A. 100% maternal
B. 50% maternal and 50% foetal
C. 100% Foetal
D. 75% foetal and 25% maternal.

Answer 1

Hint: Umbilical cord is the birth cord, it is the conduit between the placenta and developing embryo. It is the genetic part of the fetus, that contains two arteries and one vein that is buried in Wharton’s jelly. Umbilical veins transport the oxygenated and nutrient-rich blood from the placenta.

Complete answer:
The fetus is an unborn child that is present in the uterus which is attached to the placenta with the uterus wall. The umbilical cord is connected with the placenta. The umbilical cord enters the fetus abdomen and the umbilical veins move toward the fissure of the liver and then split into two and one of the veins join the hepatic system and the second join the inferior vena cava that carries blood toward the heart. Umbilical cord develops from allantois and contains some yolk sac. That cord is not directly linked with the mother but joins the placenta, which helps in transferring material from mother to embryo and from embryo to mother. So, the umbilical cord carries two arteries and one vein, which carry deoxygenated blood and oxygenated blood respectively. The blood which carries in the umbilical cord is exclusively fetal blood and no mixing of maternal and fetal blood if the mother and fetus carry different blood groups then the mixing of blood can cause coagulation of blood or agglutination, which leads to death of the fetus or mother.
Hence, the correct answer is option (C).

Note: Numbers of problems occur due to dysfunctioning of the umbilical cord that can affect mother and fetus such as umbilical cord compression, velamentous cord insertion, umbilical cord prolapse, single umbilical artery.