The volume of blood coursing the blood circulation is approximately five litres. A typical vein will stretch about eight times as much as corresponding artery. Because veins have high capacitance, large changes in blood volume have little effect on arterial blood pressure. If the volume rise or falls, the elastic walls stretch or recoil, changing the volume of blood thus blood pressure in the nervous system.
What else tissues can we consider? I am interested in blood circulation and blood pressures in different tissues.