Unoxygenated blood enters the systemic circulation in children with tetralogy of Fallot because:
A) the aorta and pulmonary artery have exchanged positions.
B) pulmonary stenosis changes the ventricular pressures.
C) the left ventricular wall has hypertrophied.
D) the septal defect allows exchange of blood between the atria.

Question

Quizplus · Accepted Answer

In tetralogy of Fallot, pulmonary stenosis increases right ventricular pressure, causing right-to-left shunting through the ventricular septal defect, leading to unoxygenated blood entering the systemic circulation.

Unoxygenated Blood Enters the Systemic Circulation in Children with Tetralogy