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beta blockers

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drpkaur
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08/13/06 - 11:08 AM

beta blockers used as antihypertensives will have effect on which of the foll nephron segements

a. afferent artriole
b macula densa
c. efferent arteriole
d. afferent arteriole, efferent arteriole and macula densa
e macula densa and afferent arteriole

new_n_lost
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08/13/06 - 01:37 PM

Ans A cos the Afferent arteriole has JG cells which r innervated by the Sympathetic gamglion. the JG apparatus is formed by the Macula Densa, Laci cells n the JG cells. the Macula densa reponse is to Renin but not to Beta Stimulation.

Correct if i m wrong plz.

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drpkaur
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08/13/06 - 09:31 PM

try again ..

PatriciaLim
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08/20/06 - 03:38 PM

B blocker used as anti hypertensive decreases renin.
Renin is secreted by JG cell and thats a modified smooth muscle of afferent arterioles and macula densa.
so E?

jedw
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08/23/06 - 01:59 AM

what's the correct anwser?

afferent arteriole has JG cells (secreting renin) with beta-receptors, so they should
be bloked -> ans. seems A ?!

drpkaur
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08/23/06 - 08:20 AM

Ans is D.....

JG apparatus consists of the JG cells in the afferent arteriole and the macula densa...beta blckers directly act on the jg apparatus..
however by decreasing renin they also dec angitoensin 2 which has an effect on the efferent arteriole

muzammil
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08/23/06 - 01:08 PM

nice question

MRMAVERICK
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08/24/06 - 12:05 AM

YUP NICE QUESTION shocked

anu_usmle
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08/24/06 - 02:48 PM

Excellent Q.

Thanks for posting!

Leopard
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09/03/06 - 03:29 PM

#10

drpkaur wrote:
Ans is D.....

JG apparatus consists of the JG cells in the afferent arteriole and the macula densa...beta blckers directly act on the jg apparatus..
however by decreasing renin they also dec angitoensin 2 which has an effect on the efferent arteriole

By the way there are two objections
1:Whenever some effect is asked it is usually "direct effect
2:You did not explain are there beta receptor on macula densa also?

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goharpakistan
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09/14/06 - 08:46 AM

#11

goharpakistan
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09/14/06 - 08:46 AM

#12

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