TPR and mean systemic pressure

[cage92]

in fa cardiovascular function curve table : change in tpr do not change mean systemic pressure>?it is confusing is mean systemic pressure= blood pressure? and how tpr has no effect? please i need an explanation

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[Apoplexy__]

Mean arterial pressure (MAP) = 2/3 (diastolic BP) + 1/3 (systolic BP)
Also, MAP = CO x TPR

Therefore, CO x TPR = 2/3 (diastolic BP) + 1/3 (systolic BP).

So TPR increases MAP because it increases both diastolic and systolic BP. A change in TPR that doesn't change the same direction as blood pressure would likely be because another variable of BP such as intravascular volume was changed (e.g. hypovolemia --> low BP --> compensatory increased TPR).

 

[cage92]

thank your for your explanation so the conclusion that mean systemic pressure will not change in vascular function curve if we change the tpr bcz msp has many factor ?

 

[Apoplexy__]

thank your for your explanation so the conclusion that mean systemic pressure will not change in vascular function curve if we change the tpr bcz msp has many factor ?

Sorry, I misunderstood what you were referring to in your original question. You're talking about the x-intercept of the vascular function curve...yeah, apparently the concept of "venous resistance" wasn't supposed to necessarily be the same as TPR, so there's a little bit of controversy about the whole thing. See http://www.pathwaymedicine.org/vascular-function-curve

I'd just memorize that FA says TPR changes the slope, memorize what factors do that, and leave it at that.