Carry oxygenated blood away from the heart and have thick walls, with the pulmonary artery as the exception.

• A. Veins
• B. Arterioles
• C. Arteries
• D. Capillaries

Answer: (C)

Arteries are the vessels that carry blood away from the heart and have thick, muscular walls to withstand the high pressure of blood being pumped out with each beat. In systemic circulation, they mostly carry oxygen-rich blood to tissues. The pulmonary artery is a well-known exception: it carries blood away from the heart to the lungs but with low oxygen content. Veins return blood to the heart and have thinner walls (often with valves), capillaries are tiny exchange vessels, and arterioles are small branches of arteries that still carry blood away from the heart but are narrower and not as thick-walled as the main arteries. So the statement best describes arteries.