Postural changes and blood pressure, Please help!

[Disinence2]

This question has been driving me crazy!

The normal cardiovascular response to assumption of the upright posture includes

A. Increased mean aortic pressure
B. Increased aortic pulse pressure
C. Increased aortic systolic pressure
D. Increased aortic diastolic pressure
E. Increased aortic arch pressure

If anyone can explain this too me it would be greatly appreciated. I seem to be able to make physiological arguments for just about all the answer choices.

Thanks!

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[heysexylady]

This question has been driving me crazy!

The normal cardiovascular response to assumption of the upright posture includes

A. Increased mean aortic pressure
B. Increased aortic pulse pressure
C. Increased aortic systolic pressure
D. Increased aortic diastolic pressure
E. Increased aortic arch pressure

If anyone can explain this too me it would be greatly appreciated. I seem to be able to make physiological arguments for just about all the answer choices.

Thanks!

I want to say the answer is an increase in MAP b/c of the fact that when someone stands up quickly...there is a decrease in Venous return due to increase gravity (hydrostalic pressure) on the lower limb veins

So decrease in central venous pressure, decrease in venous return, decrease in end diastolic pressure, decrease in stroke volume ( which will also lead to a decrease in pulse pressure), decrease in cardiac output and so a decrease in mean arterial pressure.

The barorceptors will respond to the decrease in MAP by sending decreasing action potentials to the medulla and so will promote the cardioaccelatory center and vasomotors center to increase sympathetic activity and decrease the activitiy of the cardioinhibitory center ( less parasympathetic activity). Increase in symp activity will lead to venoconstriction ( Increase VR--> increase MAP), will lead to vasoconstriction (increase in TPR--->increase MAP), will lead to higher contractility ( increase cardiac output----> increase MAP)

I could be wrong about the answer ...but I would say A.

 

[Disinence2]

That's the best argument for A I have heard yet!

The stated correct answer is D. Which for me is one of the harder choices to rationalize. I've been waiting to hear back for the professors reasoning.

Thanks for your response.

 

[digitalising]

This question has been driving me crazy!

The normal cardiovascular response to assumption of the upright posture includes

A. Increased mean aortic pressure
B. Increased aortic pulse pressure
C. Increased aortic systolic pressure
D. Increased aortic diastolic pressure
E. Increased aortic arch pressure

If anyone can explain this too me it would be greatly appreciated. I seem to be able to make physiological arguments for just about all the answer choices.

Thanks!

Is the question be referring to the reaction prior to baroreceptor activation or after?

Prior to activation, we'd have decreased CO for the reason stated by HSL (decreased VR). So evaluating the answers based on that:

A - Opposite because decreased CO means that aortic pressures will fall as less blood is flowing through the aorta.

B - This would either fall or remain constant, but certainly wouldn't increase since the heart is ejecting less blood.

C - Again, heart is ejecting less blood, so aortic systolic BP would fall compared to normal.

D - A lot of the force that moves blood away from the heart is the momentum of the blood being ejected from the heart. If the CO has decreased, less blood is ejected and thus this moving force is lost to some extent. Blood would accumulate in the aorta and thus increase diastolic pressure. Less ejection also means less distension of the wall of the aorta - the elastic recoil is also responsible for moving blood into the periphery, and without an adequate amount of blood to physiologically widen the aorta, this evacuation mechanism is also lost.

E - Again, this would decrease because of the loss of CO.

If it's after the baroreceptor response has been initiated, then all of them seem reasonable - increase in HR to improve CO would increase all of the proximal pressures, except possibly D.

 

[turkeyjerky]

That's the best argument for A I have heard yet!

The stated correct answer is D. Which for me is one of the harder choices to rationalize. I've been waiting to hear back for the professors reasoning.

Thanks for your response.

D makes sense to me. The baroreceptor response leads to increased HR which causes increased diastolic BP (think of it like the bp has less time to fall from its peak during systole).

The rest of the choices are incorrect.

A--MAP should be restored to its original value, but it won't actually be increased.

B--PP will actually decrease, b/c systolic pressure decreases (see below) and diastolic increases.

C--SP decreases due to decreased SV following the reduction in venous return.

E--I don't even know what this means, it sounds like a restatement of choice A.

 

[Veg]

This question has been driving me crazy!

The normal cardiovascular response to assumption of the upright posture includes

A. Increased mean aortic pressure
B. Increased aortic pulse pressure
C. Increased aortic systolic pressure
D. Increased aortic diastolic pressure
E. Increased aortic arch pressure

If anyone can explain this too me it would be greatly appreciated. I seem to be able to make physiological arguments for just about all the answer choices.

Thanks!

Stat consult for Dr. Costanzo!

http://www.amazon.com/Physiology-Bo...bs_sr_1?ie=UTF8&s=books&qid=1238172892&sr=8-1

 

[flaahless]

I think D is just a fancy way of saying increased systemic vascular resistance, which would occur in this situation.

Also, the other answers have some component of systolic activity, which should all be decreased due to the low CO, not increased.