The primary structures of the lymphatic and immune systems in the lower extremities are the lymph vessels. The large bones of the leg are also important, as these contain bone marrow that produces a large number of lymphocytes.
The lymphatic system works closely with the immune system. Lymph nodes trap pathogens so that antibodies can attack them. The byproducts of this attack (dead bacteria ormycontentbreak viral particles and dead or damaged antibodies and white blood cells) can then be flushed out of the body along with the lymph fluid. This prevents excessive buildup in the body of the poisonous products of cellular decay.