As a result of blockage in the pulmonary artery, blood would first back up into the:

a. aorta.
b. left ventricle.
c. pulmonary veins.
d. right ventricle.

ANS: D
Blockage in the pulmonary artery would cause blood to back up into the right ventricle, not the aorta since these two vessels do not communicate. The pulmonary artery and left ventricle do not communicate. Blockage in the pulmonary artery would not cause blood to back up into the pul-monary vein since the pulmonary vein takes blood to the left atrium.