The spleen is the largest organ of the:

• A. Endocrine system
• B. Nervous system
• C. Digestive system
• D. Lymphatic system

Answer: (D)

Think of the lymphatic system as the body's immune and drainage network, which includes structures like lymph nodes, thymus, tonsils, and the spleen. Among these, the spleen is the largest organ. It has two major roles: white pulp handles immune responses to pathogens in the blood, while red pulp filters the blood, removing old red blood cells and serving as a reservoir for platelets. This makes it a key lymphatic/immune organ, even though it sits near the stomach and is sometimes associated with digestion. The liver is larger overall but belongs to the digestive/hepatic system, not the lymphatic system. So the spleen is the largest organ of the lymphatic system.