Which is the primary function of veins?

Which is the primary function of veins?

• A. To carry blood toward the heart
• B. To carry blood away from the heart
• C. To exchange gases with tissues
• D. To supply oxygen to tissues

Answer: (A)

Veins are the vessels that return blood to the heart. Their main job is to move blood back toward the heart so it can be pumped again through the circuit. This venous return is what distinguishes veins from arteries, which carry blood away from the heart to tissues. Gas exchange happens in the capillaries, not in veins, so veins aren’t primarily responsible for exchanging gases. Likewise, delivering oxygen to tissues is a job of arteries and arterioles, not veins. An exception to the general rule is the pulmonary circulation, where some veins carry oxygenated blood back toward the heart, but the overall function of veins remains returning blood to the heart.

Veins are the vessels that return blood to the heart. Their main job is to move blood back toward the heart so it can be pumped again through the circuit. This venous return is what distinguishes veins from arteries, which carry blood away from the heart to tissues. Gas exchange happens in the capillaries, not in veins, so veins aren’t primarily responsible for exchanging gases. Likewise, delivering oxygen to tissues is a job of arteries and arterioles, not veins. An exception to the general rule is the pulmonary circulation, where some veins carry oxygenated blood back toward the heart, but the overall function of veins remains returning blood to the heart.