The function of the lymphatic system is to maintain fluid balance, support the immune system, and facilitate the absorption of fats from the digestive tract. It collects excess interstitial fluid and returns it to the bloodstream, preventing fluid buildup in tissues. Additionally, the lymphatic system transports lymphocytes, a type of white blood cell, which helps defend the body against infections and diseases. By filtering and removing pathogens from lymph fluid via lymph nodes, it plays a crucial role in the body's overall immune response.