Efferent vessels perform which function?

• A. Circulate blood
• B. Take filtered lymph away from the node
• C. Produce lymph
• D. Bring filtered lymph to the node

Answer: (B)

Efferent lymphatic vessels carry lymph away from a lymph node after it has been filtered. As lymph flows through the node, macrophages and lymphocytes screen for pathogens and present antigens. Once filtration is complete, the lymph exits through the efferent vessels at the hilum and travels on to larger lymphatic vessels, eventually joining the venous system via the thoracic duct or right lymphatic duct. This setup ensures the lymph is cleaned before it leaves the node and continues circulating.

Circulating blood isn’t handled by lymphatic vessels, so that option isn’t correct. Lymph isn’t produced by the node—it’s formed from interstitial fluid and then filtered. Bringing filtered lymph to the node is the job of the afferent vessels, not the efferent ones.