Choose the odd one out from the following terms and name the category to which the others belong:
Pulmonary artery, Renal artery, Coronary artery, Hepatic artery
Topic: Arteries carrying oxygenated blood
Answer
Odd one out: PULMONARY ARTERY. Category of the others: ARTERIES THAT CARRY OXYGENATED BLOOD.
All four are arteries, so the division is by what they CARRY.
The renal, coronary and hepatic arteries all carry OXYGENATED blood to the kidney, the heart muscle and the liver respectively — following the general rule that arteries carry oxygenated blood away from the heart.
The PULMONARY ARTERY is the great EXCEPTION: it carries DEOXYGENATED blood from the right ventricle to the lungs to be oxygenated.
THE RULE THAT NEVER FAILS: an artery is defined by DIRECTION, not by oxygen — it carries blood AWAY from the heart. The pulmonary artery obeys that rule perfectly; it is only the oxygen that is unusual.
The other exception is the PULMONARY VEIN, which carries oxygenated blood — and the umbilical vessels in a foetus, which reverse in the same way.