skeletal muscle and hypertension... wtf

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this question has been bothering me. someone please shed some light

question from qbook (physio test 2, #20)

basically, a man with high blood pressure, HR 90bpm, what's DECREASED in the skeletal muscle of his legs:

a) adenosine levels
b) arterial BP
c) arteriolar resistanc
d) blood flow
e) venous o2 concentration









answer is A... wtf. the explanation was that there's autoregulation of flow in his skeletal muscle in order to maintain blood flow despite high blood pressure. high blood pressure produces high flow and decreasing adenosine (normally vasodilates) results in vasoconstriction and thereby decreases flow to maintain it at a "normal" level.

what i am confused about is why high blood pressure results in increased arteriolar flow in the skeletal muscles. i thought with high blood pressure, there's decreased flow because it's harder for blood to flow through when resistance is high?

so what is it? high bp (high resistance) --> high flow? (high flow doesn't mean high velocity.........)

 

[t33sg1rl]

alright, so here is one interpretation:

BP increases -> flow increases everywhere -> increased flow brings in more O2 -> adenosine is converted to ATP -> low adenosine removes a critical vasodilatory stimulus, allowing vasoconstriction and therefore autoregulation.

With high pressure, the flow is always higher. That's why the autoregulating organs like brain have to vasoconstrict when the pressure goes up, so that they can maintain a constant amount of blood and you don't have blood pouring out of your eye sockets every time you go jogging.