kate_
Forum Junior
Topics: 7
Posts: 41
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Linda Costanzo: (cardiac and vasc. func curves)
When TPR is increased for a given atrial pressure, there is a decrease in venous return to the heart, i.e. vasoconstriction of arterioles decreases blood flow from arteries to the veins and back to the heart.
UW: Pulmonary capillary wedge pressure equals the pressure in left atrium. It is increased after administration of alpha- adr. agonist due to increase in peripheral vascular resistence and higher venous return to the heart.
also UW: Increased TPR causes more blood to remain on the arterial side of circulation, thus decreasing venous return. ---> how can constricted arterioles contain more blood???
my Q: does TRP increase ot decrease venous return to the heart???
I got 2 Qs wrong (in one block) and the explanations TPR-venous return are just opposite.
Please someone expl...
Thanks.
Edited by kate_ on 06/20/08 - 04:25 PM
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| Jackofknives
Ipwnpoker.com
Topics: 91
Posts: 718
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increase in TPR increases venous return because increase vessel tonus causes mean systemic filling pressure to rise. And you know venous return is directly related to MSFP - right atrial pressure.
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| shazbaz
Forum Junior
Topics: 15
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well alpha agonist would also cause constriction of veins so that would definitely increase venous return...but i guess when they just say increase in TPR then there is constriction of arterioles and so less blood going to veins and hence decreased venous return according to their explanation. as for other part of ur question...the arterioles are constricted so there is more blood in the bigger arteries and other arteries not just the arterioles..hope that made sense
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| littledoc
Forum Newbie
Topics: 5
Posts: 62
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i think venous return is proportional to CO, so when TPR is increased CO is decreased & so venous return & opp. tell me if i m wrong
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