Which statement about the lymphatic system is correct?

• A. It drains into arteries instead of veins.
• B. It begins in tissue spaces and ends at major veins.
• C. It does not interact with the circulatory system.
• D. It transports oxygen to tissues.

Answer: (B)

Fluid balance and return to the bloodstream is what the lymphatic system does. Lymphatic capillaries are tiny, blind-ended vessels in tissues that collect interstitial fluid that leaks from blood capillaries. This fluid becomes lymph and travels through progressively larger lymphatic vessels, often through lymph nodes for immune screening, and finally drains into the venous system—mainly via the left thoracic duct into the left subclavian vein and the right lymphatic duct into the right subclavian vein. That path shows clearly that the system begins in tissue spaces and ends at major veins, rejoining the circulatory system. It does not drain into arteries, it does interact with the circulatory system by returning fluid, and it does not transport oxygen (that’s done by blood).