Dear all,(adsbygoogle = window.adsbygoogle || []).push({});

I am trying to find a mathematical explanation for why a blood vessel's lumen, especially an artery's, expands when the heart forces blood through the vessel upon contraction of the myocardium. This expansion is clearly evident when taking a person's pulse.

I have some ideas but I am quite confused considering all of the variables.

Firstly, I took the idea of volumetric flow rate and worked from there:

[tex]Q=A\cdot v[/tex]

Q blood flow rate through the vessel (volume per unit time)

A cross-sectional area of the vessel lumen

v velocity of blood flow

Now I seem to remember that (area)(velocity) = constant, though this would imply that the the vessel would constrict as the velocity of the blood increases after a heart contraction!?

I then took A, the cross-sectional area of the vessel lumen, and considered it in relation to blood pressure(from the pressure formula):

[tex]A=\frac{F}{p}[/tex]

F force exerted on the vessel wall by the blood

....AND there I got stuck. It has been annoying me all day and I would quite like to find an answer for it! I seem to be unable to link my medical knowlege with my physics knowlege at this point - perhaps I'm looking at the wrong variables.

Many thanks,

James

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# Arterial blood flow

Can you offer guidance or do you also need help?

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