“…Studies of the effects of posture on diuresis support the view that the effective distribution of blood rather than its total volume is important in influencing renal behavior (6,40,41). The great veins (42), the right heart and pulmonary artery (43), the cranial cavity (44), the "cephalad portion of the body" (45), and the arterial pressoreceptors (46) (50,51), and hemorrhage (52,53) are associated with a diminution in total blood volume. In quiet standing (6), venous congestion of the limbs (54,55), partial occlusion of the superior or inferior vena cava (56), and portal hypertension (57), filtration from the capillaries is increased and in addition blood is pooled in the peripheral veins, away from the general circulation.…”