Final answer:
Pulmonary arteries carry deoxygenated blood from the right side of the heart to the lungs, while pulmonary veins bring oxygenated blood back to the left side of the heart.
Step-by-step explanation:
The blood vessels that carry deoxygenated blood from the right side of the heart to the lungs and bring oxygenated blood back to the left side of the heart are called pulmonary arteries and pulmonary veins.