Question

Which of these statements is correct? a. Fetal circulation, like adult circulation, takes blood equally to a pulmonary circuit and a systemic circuit. b. Fetal circulation shunts blood away from the lungs but makes full use of the systemic circuit. c. Fetal circulation includes exchange of substances between fetal blood and maternal blood at the placenta. d. Unlike adult circulation, fetal blood always carries \(\mathrm{O}_{2}\) -rich blood and therefore has no need for the pulmonary circuit. e. Both b and c are correct.

Short answer

Both b and c are correct.

Step-by-step solution

Statement a

Fetal circulation, like adult circulation, takes blood equally to a pulmonary circuit and a systemic circuit. This statement implies that fetal circulation is the same as adult circulation. However, that's not the case. In the fetus, blood flows differently, and the lungs are nonfunctional until birth. So, this statement is incorrect.

Statement b

Fetal circulation shunts blood away from the lungs but makes full use of the systemic circuit. This statement implies that fetal circulation allows blood to bypass the lungs, which is true. In the fetus, blood bypasses the lungs through some specific structures called the foramen ovale, and the ductus arteriosus allowing blood to bypass the pulmonary circulation. This helps in making full use of the systemic circuit. So this statement is correct.

Statement c

Fetal circulation includes the exchange of substances between fetal blood and maternal blood at the placenta. In fetal circulation, the placenta is the primary site for the exchange of nutrients, oxygen, and waste products between the mother and the fetus. Without the placenta, the fetus would not receive the necessary nutrients and oxygen required to survive and grow. So, this statement is also correct.

Statement d

Unlike adult circulation, fetal blood always carries \(\mathrm{O}_{2}\)-rich blood and therefore has no need for the pulmonary circuit. Although it's true that fetal blood has higher oxygen content than adult blood because of the presence of fetal hemoglobin, the fetal circulation does partially use deoxygenated blood, which would eventually mix with oxygenated blood to supply the fetus. However, it doesn't mean the fetus has no need for the pulmonary circuit. The statement is misleading and is incorrect.

Statement e

Both b and c are correct. We have established that both statements b and c are correct, which means statement e is also correct. The correct answer is: \e Both b and c are correct.