What important function do two sets of peripheral veins serve in the neck and limbs?

• A. Controlling body temperature
• B. Returning blood to the heart
• C. Carrying oxygen
• D. Immune defense

Answer: (A)

The main function of these peripheral veins in the neck and limbs is to return blood to the heart. They form two parallel systems—the deep veins that run alongside arteries and the superficial veins in the skin—and together drain the tissues so blood can be carried back to the central circulation. Valves prevent backflow, and the muscle pumps in the limbs help push blood upward toward the heart, with the neck veins guiding flow toward the superior vena cava. In the neck, blood from the head and face drains through the jugular veins into the central venous system. While skin veins can contribute to heat loss by dilating or constricting to regulate heat exchange, the essential role of this venous network is venous return, not thermoregulation. Carrying oxygen is the job of arteries (and, at the tissue level, capillaries), and immune defense is a broader function of the circulatory system, not the defining purpose of these veins.