Which statement best describes veins?

• A. They carry blood under high pressure with thick muscular walls
• B. They have low resistance to blood flow due to large lumens and valves
• C. They have low pressure and thin walls
• D. They operate with velocity higher than arteries

Answer: (C)

Veins are designed as capacitance vessels that return blood to the heart at low pressure. Their walls are thinner and less muscular because they don’t have to withstand the high pressures seen in arteries. The large lumens give veins a high capacity to hold blood, which is why they serve as reservoirs in the circulation. Valves within many veins help prevent backflow and, together with skeletal muscle contractions, assist the return of blood to the heart against gravity. In contrast, arteries carry blood under high pressure and have thick, muscular walls to manage that force, and the flow in arteries is typically faster. So describing veins as having low pressure and thin walls best captures their structural and functional role.