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  #1  
Old 06-22-2011
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Vascular Organ Blood Flow...

1.- If a coronary artery is occluded for one minute and then the occlusion is released,

a) A period of active hyperemia follows.
b) Coronary flow will increase because of vasoconstriction occurring during the ischemia.
c) Endothelial release of nitric oxide will contribute to the reactive hyperemia.
d) Interstitial adenosine concentrations will increase and constrict coronary arterioles.


2.- Which one of the following organ circulations is most strongly constricted during sympathetic activation resulting from a baroreceptor reflex when a person suddenly stands up?

a) Brain
b) Heart
c) Intestine
d) Skin

.

Last edited by bebix; 06-22-2011 at 02:07 PM. Reason: added qs
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Old 06-22-2011
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Quote:
Originally Posted by bebix View Post
1.- If a coronary artery is occluded for one minute and then the occlusion is released,

a) A period of active hyperemia follows.
b) Coronary flow will increase because of vasoconstriction occurring during the ischemia.
I'll guess:

1) B)
2) D) Im guessing Skin because it is the largest organ so it'll have the most blood supply, and it would be the most effective to increase preload..
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Old 06-22-2011
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I will go with

1) B ( Are we talking about steel phenomenon? ) Redistribution of the Coronary flow due contraction of the ischemic part to supply the "normal part" increasing the damage to the already ischemic part?

2) D Same as PatelMd Explanation...
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Old 06-22-2011
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Quote:
Originally Posted by bebix View Post
1.- If a coronary artery is occluded for one minute and then the occlusion is released,

a) A period of active hyperemia follows.
b) Coronary flow will increase because of vasoconstriction occurring during the ischemia.
c) Endothelial release of nitric oxide will contribute to the reactive hyperemia.
d) Interstitial adenosine concentrations will increase and constrict coronary arterioles.


2.- Which one of the following organ circulations is most strongly constricted during sympathetic activation resulting from a baroreceptor reflex when a person suddenly stands up?

a) Brain
b) Heart
c) Intestine
d) Skin

.
1. i guess it's A
2 Skin D
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  #5  
Old 06-22-2011
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After reviewing this...

i think answer B is not correct, because on ischemic cardiac tissue there is endothelial release of nitric oxide will contribute to the reactive hyperemia, The increase in flow (reactive hyperemia) following release of the occlusion causes a flow-dependent release of nitric oxide by the vascular endothelium, which further contributes to the increase in blood flow.

Actually i have to read through all my notes to get this answer,,, it was beeeping into my brain.. =)

Answer B is more likely to vasodilate by depletion of adenosine,, so i dont think it will contract...

So I go with Answer C...

Thanks Bebix! good one...
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Old 06-22-2011
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Correct Answer correct answer

1.- The correct answer is c because the increase in flow (reactive hyperemia) following release of the occlusion causes a flow-dependent release of nitric oxide by the vascular endothelium, which further contributes to the increase in blood flow.
Choice a is incorrect because active hyperemia is associated with increased tissue metabolic activity and not with postischemic hyperemia.
Choice b is incorrect because vasodilation occurs during ischemia.
Choice d is incorrect because increased interstitial adenosine dilates coronary arterioles.


2.- The correct answer is c.
Choice a is incorrect because the brain responds little to sympathetic activation. Although the coronary vasculature in the heart (choice b) is capable of responding to sympathetic activation, concurrent stimulation of heart rate and inotropy lead to meta- bolic vasodilation.
Choice d is incorrect because sympathetic control of the skin circulation is primarily related to thermoregulation; therefore, the baroreceptor reflex associated with standing has little influence on cutaneous blood flow.
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Default 1.c

NO and Adenosine (a product of ATP degradation) are powerful for autoregulation of blood flow in coronary arteries. As the systolic blood flow through coronary arteries is only 20% of normal these local vasodilators (others are bradykinin, serotonin,prostaglandins, ANS neurotransmitters, mechanical shear stress, endothelin) endothelial NO synthase. eNOS in the endothelium of coronary arteries makes NO from Arginine and oxygen. released in response to ACh and NE.
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