which tissue produces lymphocytes and filters out impurities and harmful substances
Lymph vessels. Walled, valved structures that carry lymph around the body. Lymph nodes. Small bean-shaped glands that produce lymphocytes, filter harmful substances from the tissues, and contain macrophages, which are cells that digest cellular debris, pathogens and other foreign substances. Major groups of lymph nodes are located in the tonsils, adenoids, armpits, neck, groin and mediastinum.