The force moving electric current is voltage. The force moving liquids is pressure. Each of these are basic laws of physics derived from the Second Law of Thermodynamics. The mnemonic Ohm’s law can be applied to either one.
Blood is moved by pressure through whatever resistance there may be with the resulting flow. It is essentially impossible to image or describe a vascular bed so the resistance to the flow of blood has to be measured. This is in distinction to a single pipe or tube of known length and diameter which allows a resistance to be calculated. In this way blood flow through the vascular tree is different from fluid flow through a tube or pipe. We can only know the resistance to blood flow by measuring it, not by calculation.
The force driving blood through the cardiovascular system is the pressure in the aorta minus the Central Venous Pressure or CVP. Since CVP is always very low relative to Aortic Pressure is it common to use simply aortic pressure to represent this force.
The equation CO = BP/SVR describes the relationship between flow and energy in the cardiovascular system. This is Ohm’s Law of Blood Flow. The use of the term Olm’s law of blood flow is preferred rather than Olm’s law for fluid flow it emphasize that the resistance can only be measured and not calculated. This is a physical concept not a biological concept. There is no reason to require experimental evidence for its validity. By this we know that increasing resistance in the system by for instance using a vasoconstrictor will reduce flow.
It is a leap of faith that using a vasoconstrictor will increase flow or perfusion through important vascular beds such as the brain or myocardium. We should expect the opposite. This myth is discussed elsewhere.