Lymph nodes take special place among other organs, because of simultaneous realization of a drainage of interstitium and immune function. It is represented relevant to estimate influence of parameters of hydration on forming of the morphofunctional status of regional lymph nodes. High efficiency and sustainability of lymph nodes depends on hydration characteristics and it is connected with an originality of drained lymphatic regions. It is shown that different lymph nodes differ on the content of the common water and fractions of water. The mesenteric lymph node distinguishes the bigger content of the common water in comparison with inguinal and tracheobronchial lymph nodes. The coefficient of hydration and degree of density define a consecutive row of lymph nodes: inguinal - mesenteric - tracheobronchial, pointing to their different participation in a drainage of the served lymphatic region. Parameters of hydration are comparable to forming of morphological variant of structure and functional specialization of regional lymph nodes. The originality of the lymphatic region affects functional preference of a regional lymph node, forming a certain morphological variant of structure. It is the proof of realization of the principle of a regional determinant of the concept of the lymphatic region.