Question

In the fetal heart, the lungs are deflated and the fetus receives oxygen from its mother across the placenta through the umbilical cord. There is an opening in the wall between the left and right side of the fetal heart. This should normally grow closed before birth.
What symptoms would be expected if this heart wall opening remained open?

a) It would cause hypertension; fetal blood pressure would be abnormally high.
b) This would balance the diastolic and systolic blood pressure readings.
c) Deoxygenated blood would mix with oxygenated blood and systemic circulation would have too little oxygen to sustain healthy growth.
d) This would not actually cause any bad effects at all since the heart pumping would be equally distributed between left and right ventricles.
e) This would cause blood to flow back out of the heart through the right atrium and cause drastic effects in the fetus.

Answer 1

Answer:

The preferable option will be - C.

C.  Deoxygenated blood would mix with oxygenated blood and systemic circulation would have too little oxygen to sustain healthy growth.

Explanation:

Fetal circulation  :

1. Oxygenated blood from the placenta enters the right atrium via inferior vena cava

2. The foramen ovale allows oxygenated blood in the right atrium to reach the left atrium

3. The ductus arteriosus connects the aorta with the pulmonary artery, further shunting blood away from the lungs into the aorta.

4. Mixed blood travels to the head and body and back to the placenta via the aorta.

• If the heart-opening remains open after birth, then, deoxygenated blood would mix with oxygenated blood and systemic circulation would have too little oxygen to sustain healthy growth.