RayBerg
Forum Senior
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4. About 4 to 6 days after you place a normal person on a low-sodium diet, which of the following will be observed?
A. plasma renin and aldosterone are below normal
B. plasma renin and aldosterone are above normal
C. plasma sodium concentration is below normal
D. plasma sodium concentration is normal
E. B and D are correct.
5. Renin is produced and secreted from granules located in the:
A. macula densa
B. mesangial cells
C. intercalated cells
D. afferent arteriole
E. interstitial cells
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| peraspera
Forum Elite
Topics: 38
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4. D
5. Renin made in JGA cells of Afferent arteriole
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| RayBerg
Forum Senior
Topics: 32
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For those who haven't attempted, I'm willing to bet that 90% will get one of the two questions wrong. Please make an attempt to do the q's...
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| drduck
Forum Guru
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Posts: 529
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Q number 1......E
u really scared me....i had to think...think...and think......
but back to where i was.....
i feel answer is E......
sudden dietary sodium restriction will lead to rise in renin and aldosterone levels which but, later on adjust to around normal levels....but never to original values..
and yes....serum sodium will get normalised..
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| drduck
Forum Guru
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Q number 2.....D,
this not too difficult....
is there something i have missed????
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| drduck
Forum Guru
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Posts: 529
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post answer for Q number 1 plz...
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| RayBerg
Forum Senior
Topics: 32
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Duck, yes you did miss something on #2...just like me! And I'm sure most would've done so as well.
Answers:
D
A - Btw..I picked afferent arteriole as my answer as well.
I don't want to take credit for the explanation as it was provided by another poster. But here it is..
Renin is secreted by the juxtglomerular apparatus:
The jg apparatus is composed of 3 structure:
1) granular or juxtaglomerular cells
2)macula densa
3) connective tissue cells
But the granular cells are differentiated smooth muscle in the afferent
arteriole where the arterioles junction with the glomeruli. Granular cells secrete renin. The macula densa is the specialized portion of the tubule that marks the transition from the acending loop of Henle to the distal tubule. This nephron segment always touches the afferent arteriole and glomerulus from its own nephron of origin , and the macula densa, themselves are in intimaate contact withe granular cells .Evidence suggest that the macula densa contributes to the control of renin secretion. Whew!
Feedback Please
Ref.--Renal Physiology by Arthur Vander.
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| drduck
Forum Guru
Topics: 82
Posts: 529
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those really were mind blowing problems......
explanation for 2 was fine but i have to read by myself.....
about 1.....how come there is no increase in level of renin and aldosterone.....and so how come the sodium level was normal in blood???
plz post explanation.....
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| Ig F
Forum Elite
Topics: 3
Posts: 439
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for question 1.its D.....
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i m not perfect but i wanna get close to it......
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| zeeec2000
Forum Junior
Topics: 21
Posts: 48
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for q 1 should E unless the increase will be only in Aldesteron not Renin so in this case will be D
I need to conferm if the low salt diet will increase the renin or not??
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| paheli
It'sAllAboutGoodKarma
Topics: 177
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kaplan says quite clearly that macula densa does NOT secrete renin. it only senses Na conc, and stimulates juxtaglom cells to secrete it
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Prepare as if you're the worst, Perform as if you're the best! As you dream, so you manifest. So, DREAM BIG!! When you face hardship, remember, God never gives you more than you can handle. Keep your face to the sunshine and you cannot see the shadows.
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| tompat
Forum Elite
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hey ray
sorry buddy cud u please explain a bit more.
i think ans for 1 is E and for 2 it's D cuz even though macula densa is the controller of renin secretion , it 's secreted by J-G cells which are located in afferent arterioles. while macula densa is the specialized part of DCT.
and can u also explain why there aint any increase in renin and aldosteron.
i think to maintain higher level of Na+ absorption there shud be an elevated level of renin and aldosteron.
please let me know if i m making any gross mistake.
hmm paheli me too as think as u drunk i m, what was the brand
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| paheli
It'sAllAboutGoodKarma
Topics: 177
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hmm....wanna know the brand? it was and is the one that USMLE specially brews for us poor souls, specifically to knock us out big time!! am still reeling from the spin!!
p.s. sorry to everyone else for saying this here, i know it's not the right place, but as you see, i'm not thinking quite right.
___________________
Prepare as if you're the worst, Perform as if you're the best! As you dream, so you manifest. So, DREAM BIG!! When you face hardship, remember, God never gives you more than you can handle. Keep your face to the sunshine and you cannot see the shadows.
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| bioguy
Forum Guru
Topics: 46
Posts: 836
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so, whats the correct answers ???????
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