cardiac physiology question

[obiwan]

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can someone clarify this?

BRS physio says that an increase in arterial pressure causes increased capillary hydrostatic pressure... however, increased tpr causes decreased venous return... it seems like the increase in tpr causes increased fluid downstream from the arterioles?? thanks

 

[airmonkey84]

You're confusing pressure and resistance, or so it seems. TPR is determined by arterioles. Higher total peripheral resistance will act like a "gate" to decrease blood flow into the capillaries, thereby decreasing capillary hydrostatic pressure.

Higher arterial pressure will just lead to more blood flow downstream into the capillaries which will thus increase hydrostatic pressure in the capillaries.

Hope this helps.

 

[obiwan]

You're confusing pressure and resistance, or so it seems. TPR is determined by arterioles. Higher total peripheral resistance will act like a "gate" to decrease blood flow into the capillaries, thereby decreasing capillary hydrostatic pressure.

Higher arterial pressure will just lead to more blood flow downstream into the capillaries which will thus increase hydrostatic pressure in the capillaries.

Hope this helps.

wouldn't an increase in TPR lead to an increase in arterial pressure though?

 

[airmonkey84]

Yes, you are right it would lead to an increase in arterial pressure. I'm pretty sure that when they say that arterial pressure increases lead to an increase in capillary hydrostatic pressure, they are assuming that TPR remains constant.