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Old 07-13-2012
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Kidney Effects of afferent renal vasoconstriction

In experimental settings, diameter of a renal artery is reduced to 75%. One week later, functional mesaurements are taken and compared to baseline values. Which of the following is most likely to be increased from baseline as a result of this experiment?

A. GFR
B. Glomerular capillary hydrostatic pressure
C. Glomerular filtration coefficient
D. Filtration fraction
E. Urine flow rate

Can someone explain please?

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Old 07-14-2012
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D. Filtration fraction-Increased

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Old 07-14-2012
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Dddd
-vasoconstriction at the afferent arteriole cause decrease in GFR and RPF therefore FF remains constant at the afferent(note FF=GFR/RPF)
-while vasoconstriction at efferent arteriole deccrease RPF but increase GFR hence FF is increased at efferent

my deduction;FF will ultimately increase (hope am right)
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Quote:
Originally Posted by imgchuchu View Post
Dddd
-vasoconstriction at the afferent arteriole cause decrease in GFR and RPF therefore FF remains constant at the afferent(note FF=GFR/RPF)
-while vasoconstriction at efferent arteriole deccrease RPF but increase GFR hence FF is increased at efferent

my deduction;FF will ultimately increase (hope am right)


didn't know u where posting answer
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Old 07-14-2012
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Quote:
Originally Posted by imgchuchu View Post
Dddd
-vasoconstriction at the afferent arteriole cause decrease in GFR and RPF therefore FF remains constant at the afferent(note FF=GFR/RPF)
-while vasoconstriction at efferent arteriole deccrease RPF but increase GFR hence FF is increased at efferent

my deduction;FF will ultimately increase (hope am right)
yes they say the answe is D.
but, since the constricted the renal artery that would decrease both the GFR and the Renal plasma flow! So FF should remail the same??? I dont see why it would increase!
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Old 07-14-2012
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what the hell is Glom. filtration coefficient??

I was pretty sure that the other options cant be the right answer, so I thought this would be the answer but I guess I was wrong.. Yeah increased FF doesn make sense to me either. There would be no change there.
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Originally Posted by numbndumb View Post
yes they say the answe is D.
but, since the constricted the renal artery that would decrease both the GFR and the Renal plasma flow! So FF should remail the same??? I dont see why it would increase!
Pressure in afferent arteriole decreases, and that causes reflex vasocontriction in the efferent arteriole(RAA). Thus, capillary hydrostatic pressure is maintained to some extent and GFR, while decreased, does not fall as much as the RPF.
So, basically GFR v and RPF vv. So filtration fraction increases.
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