What are tubular, elastic, thick-walled branching vessels that carry pure blood throughout the body called?

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

Answer: (C)

Arteries are the vessels that carry blood away from the heart under the highest pressure, so they need thick, elastic walls to withstand and smooth out the force of each heartbeat. The muscular middle layer allows vasoconstriction and vasodilation, helping regulate blood flow and pressure as blood travels to smaller arteries and arterioles before reaching the capillaries. In the systemic circulation, these vessels typically carry oxygen-rich “pure” blood to tissues, which is why this option is identified as the correct choice. By contrast, veins have thinner walls and valves to return blood to the heart, capillaries are extremely thin to facilitate exchange, and nerves are not blood vessels.