Blood Flow

[sanguinee]

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I understand blood is not an ideal fluid that does not follow Bernoulli's equation. If it does follow Bernoulli's equation, during vasoconstriction, the area decreases, thus the velocity should increase, right? Thanks!

 

[amy_k]

Yes it would cause an increase in velocity according to the continuity equation provided the flow rate is constant. However, the reason we have increased blood pressure when Bernoulli's equation tells us we should have a decrease in pressure, is not just because blood is not an ideal fluid, but also because the changes that lead to vasoconstriction also cause increase in heart rate and stroke volume, and because the "pipes" in question here are elastic vessels, not rigid tubes.

 

[amy_k]

The continuity equation gives us the relationship decreased area ---> increased velocity at constant flow rate whereas Bernoulli's equation gives us increased velocity ----> decreased pressure

 

[azor ahai]

treat it as ideal for MAP, everything else no.