The multiple choice questions have five answer choices — one (and only one) is correct in each case.
Blood flows from the heart to the lungs in the pulmonary artery and returns from the lungs to the heart in the pulmonary vein. The blood in the pulmonary artery is
Select an Answer
higher in and lower in
content than the blood in the pulmonary vein
higher in both and
content than the blood in the pulmonary vein
lower in and higher in
content than the blood in the pulmonary vein
lower in both and
content than the blood in the pulmonary vein
higher in content, but about the same in
content as the blood in the pulmonary vein
View Correct Answer
The correct answer is lower in oxygen and higher in carbon dioxide than blood in the pulmonary vein (C). Recall that arteries carry blood away from the heart. The blood in the pulmonary artery is on its way to the lungs. Oxygen has diffused out of this blood into the tissues it has passed through on its way around the body, and carbon dioxide has diffused in. In the lungs, the blood will lose much of its carbon dioxide and acquire oxygen, so the blood returning to the heart in the pulmonary vein is oxygen-rich, compared to that in the pulmonary artery.