Lymph is the fluid formed from the interstitial fluid, collected through lymph capillaries that circulates throughout the lymphatic system. There are two types of lymphoid organs involved in the production of lymph:
1. Primary- for the formation and maturation of lymphocytes which are components of lymph (bone marrow and thymus)
2.Secondary-for filtering the blood to form lymph (lymph nodes, tonsils, spleen, Peyer's patches and mucosa-associated lymphoid tissue-MALT).