Ohm’s Law is classically applied to electric current. Ohm’s Law of Fluid Flow, is an analogous law or principal that applies to the flow of fluid through a pipe or tube. Each of these is the principal of flow from high energy to low energy through some type of resistance.
The flow of blood can be describe by the same equation. In the case of blood flow we in general we can only measure resistance not calculate it. The precise configuration of the vascular tree is not knowable the way the length and diameter of a pipe is.
The general equation describing blood flow is Flow = Pressure / Resistance which for the entire body is CO= BP/SVR
Each of these are basic laws of physics
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 and determined by this equation. 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 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.
Biologically or physiologically blood flow is modulated by various mechanisms such as feedback loops and auto regulatory processes. In practice or in vivo, the data from measurements may not follow these equations precisely. In fact there may be quite significant deviations as physiologic processes work to preserve blood flow.
Generally is assumed that an intervention that raises blood pressure will increase blood flow and an intervention that reduces blood pressure will decrease blood flow. There is generally no practical alternative for making this assumption because blood pressure is so easy to measure and the actual flow of blood is essentially impossible to measure. This practice is encoded into some dogmatic and inflexible protocols and procedures. This dilemma and resultant misinformation is unfortunately, usually and frequently solved by arrogance.
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 truth or heresy is generally and unfortunately opposed by arrogance.
https://en.wikipedia.org/wiki/Heresy
In other contexts the term does not necessarily have pejorative overtones and may even be complimentary when used, in areas where innovation is welcome, of ideas that are in fundamental disagreement with the status quo in any practice and branch of knowledge.