The lymphatic system
The lymphatic system has a really complex structure including several hundred of lymph nodes, lymph vessels and capillaries spread throughout the body. The lymphatic system is closely associated with the blood circulation system.The lymph vessels return excess fluid collected from all over the body back into the blood circulation. This fluid is forced through the lymph nodes and filtered. Harmful organisms are trapped and destroyed by specialized white blood cells found in these nodes. Every day about two liters of lymph fluid flow into the blood circulation.