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....

1

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

Sure do.

2

What's vascular autoregulation?

Vascular beds will adjust in response to metabolic need.

3

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

4

2 main external inputs vascular tone?

Adrenergic
Renin, A-II, aldosterone system (RAAS)

5

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."

6

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

7

What do the vascular beds do in sepsis?

They all dilate too much.

8

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?