CV Control 3: Reg. of SVR and Flow Distrib. Flashcards Preview

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Flashcards in CV Control 3: Reg. of SVR and Flow Distrib. Deck (9)
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How can capillary networks be bypassed despite high CO?

Metarterioles can bypass capillary beds....


You know that smooth muscle cells have gap junctions, too, right?

Sure do.


What's vascular autoregulation?

Vascular beds will adjust in response to metabolic need.


3 effector mechanisms of vascular autoregulation? What's the molecular mechanism for each?

Myogenic: Increased BP -> increased SMC tone via stretch-activated Ca++ channels.
Endothelium-mediated: Sheer stress -> NO -> SMC relaxation.
Metabolic: Metabolic need (adenosine?) -> vasodilation


2 main external inputs vascular tone?

Renin, A-II, aldosterone system (RAAS)


Effect of adrenergics on the vascular beds of heart, brain, gut, renal, skin, and skeletal muscle?

Heart and brain: little change.
Renal, cutaneous, gut: vasoconstriction.
Skeletal muscle: vasodilation.
"Fight or flight."


Vascular beds are in parallel... so how do you add the resistances? (Who ever thought any of E&M physics would be useful?)

1 / R(total) = Sum of reciprocals of resistances


What do the vascular beds do in sepsis?

They all dilate too much.


When managing a patient shock, what's one thing you should worry about once you restore systemic arterial pressure?

Are they making enough urine? - i.e. has been blood been shunted away from kidneys to preserve overall bloodflow?