Lymph system; drawing shows the lymph vessels and lymph organs including the lymph nodes, tonsils, thymus, spleen, and bone marrow.  One inset shows the inside structure of a lymph node and the attached lymph vessels with arrows showing how the lymph (clear fluid) moves into and out of the lymph node. Another inset shows a close up of bone marrow with blood cells.
Anatomy of the lymph system.