Modification of lymph by lymph nodes. II. Effect of increased lymph node venous blood pressure
Adair, T.H.; Guyton, A.C.
American Journal of Physiology 245(4): H616-H622
1983
ISSN/ISBN: 0002-9513 PMID: 6624930 Document Number: 198963
Lymph nodes can change the protein concentration and colloid osmotic pressure of lymph by transfer of protein-free fluid between the blood and lymph compartments. A Starling force disequilibrium across the blood-lymph barrier causes fluid to transfer through the barrier in the direction required to establish equilibrium of Starling forces. The effect of increased lymph node venous blood pressure on efferent lymph protein concentration and efferent lymph flow was examined. An isolated dog popliteal lymph node preparation in which afferent lymph having various protein concentrations was perfused into the node at an average flow rate of 19.1 .+-. 0.3 (SD) .mu.l/min was utilized. Steady-state values of prenodal and postnodal lymph flows and protein concentrations were compared during various steady-state levels of lymph node venous blood pressure. When venous pressure was increased, the protein concentration of the efferent lymph invariably decreased and the efferent flow rate invariably increased. Evidently, an average of 96% of the change in lymph protein concentration was caused by transfer of protein-free fluid through the lymph node blood-lymph barrier. The lymph node apparently functions as a fluid exchange chamber in which fluid is transferred between the blood and lymph compartments in the direction required to establish equilibrium of the Starling forces across the blood-lymph barrier.