Cardiac Function: Blood Pressure vs. Flow: Why such confusion?
In articles about cardiac function, there are errors due to a lack of understanding of the basic principles of how pumps work. I believe there is a mis-application of the pressure-flow-resistance equations. Is Flow proportional to Pressure? Equation #1: Q = kPr / r (where Q=volumetric flow rate, Pr=pressure change, r=resistance, k=some constant) From this equation we see that flow is proportional to pressure . It means that in a given section of pipe with given resistance r, if we increase the pressure difference across it, the flow will increase. Makes sense right? But, HOW is pressure created? Does the heart (or any pump) by itself "create" a certain pressure? To attempt to answer this question, let's imagine a scenario: We know that the blood pressure during Systole (the "pump") reaches about 120 (mm Hg) in a healthy human. [side note: if the systolic pressure in your arm is measured to be 120, it's probably a bit higher in the aorta because it is upstre...
