Would greater flow take precedence over velocity in pressure

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The discussion centers on the relationship between flow, velocity, and pressure in arterial systems. It highlights that while increasing flow raises velocity, according to Bernoulli's principle, this can lead to decreased pressure in inviscid flow scenarios. However, the mean arterial pressure equation indicates that pressure is determined by flow and resistance, suggesting a different dynamic in viscous flow conditions. The conversation emphasizes that in arteries, which are subject to viscous resistance, high pressure exists upstream of constrictions, while low pressure is found downstream. Ultimately, the interplay between flow and resistance is crucial in understanding arterial pressure dynamics.
hongiddong
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The equation for mean arterial pressure = flow * resistance, however, if we increase flow we would increase velocity by the equation Velocity = flow/ cross sectional area, and velocity would decrease pressure according to bernoullies law?

Which would take precedence in generating more pressure on the arterial walls?
 
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hongiddong said:
The equation for mean arterial pressure = flow * resistance, however, if we increase flow we would increase velocity by the equation Velocity = flow/ cross sectional area, and velocity would decrease pressure according to bernoullies law?

Which would take precedence in generating more pressure on the arterial walls?
Bernoulli is for "inviscid" flow -- no resistance. You have a pipe with approximately the same pressure at inlet and outlet and find that the pressure varies depending on the flow velocity. Center of the constrictions = low pressure. Wide points = ambient pressure.

An equation for pressure = flow * resistance assumes the opposite. A viscous flow. You have a pipe with a constriction. Upstream of the constriction you have a high pressure, downstream you have low pressure. The pressure drop scales with flow and with resistance. Upstream of constriction = high pressure, downstream = low pressure.

An artery is pretty much by definition "upstream" of a viscous restriction (the capillaries).

[Caveat: I have zero real world experience with medicine, blood pressure and fluid dynamics]
 
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