Original: Lymph nodes are located at intervals along the lymphatic system. Several afferent lymph vessels bring in lymph, which percolates through the substance of the lymph node, and is drained out by an efferent lymph vessel.
Simplified: The lymphatic system is a complex network of lymphoid organs, lymph nodes, lymph ducts, lymph tissues, lymph capillaries, and lymph vessels that make and transport lymph fluid from tissue to the circulatory system.