NBME F5 S2 filtration fraction

Prep for USMLE Forum

» Log in | Register

Forum

Step 1

Match

Prep4USMLE Forum » USMLE Step 1 Forum » Physiology Forum

NBME F5 S2 filtration fraction

Author

7 Posts

clar697
Forum Guru
avatar

Topics: 190
Posts: 199

07/01/08 - 08:49 AM

Which of the following is most likely to cause an increase in filtration fraction?

A) Decreased glomerular filtration coefficient
B) Increased afferent arteriolar resistance
C) Increased efferent arteriolar resistance
D) Increased plasma protein concentration
E) Increased renal blood flow

microsporus
Forum Newbie

Topics: 0
Posts: 10

07/02/08 - 07:25 AM

tdbchoco
Forum Newbie

Topics: 4
Posts: 22

07/02/08 - 10:26 AM

gladiator9
Forum Newbie
avatar

Topics: 1
Posts: 19

07/02/08 - 10:41 AM

usmlekiller
Forum Elite

Topics: 10
Posts: 532

07/02/08 - 05:39 PM

EASY C

___________________
FUTURE 99ER

littledoc
Forum Newbie

Topics: 5
Posts: 52

07/21/08 - 01:50 PM

its B
because by increasing afferent arteriolar resistance we decrease blood flow & FF= GFR/RBF.

medschoolmania
Forum Newbie

Topics: 0
Posts: 6

07/24/08 - 01:26 AM

no thats not right. ok look... if you increase the resistance at the afferent arteriole, you will decrease blood flow, and you will decrease hydrostatic pressure within the glom cappilary which decreases GFR, therefore you are wrong. in order for filtration fraction to increase with the fraction GFR/RBF...anything that constricts the AFFERENT arteriole...it will decrease GFR. since we are speaking about increasing filtraation fraction the right answer is C. by constricting the efferent arteriole, we are mimiking the effects of renin-angiotensin 2 effects, whose primary role is to increase the hydrostatic pressure in the glom cappillary, however that is a short term effect, by constricting the efferent, you also decrease blood flow to the peritubular cappilaries which reduces blood flow, which still would increase the FF.... : )

You don't have permission to post.