mistake in EK 1001 Bio?

[mytoechondriac]

This book is the bane of my existence... I freakin' hate this book. I found so many errors in it already. But I'm not sure if this is a mistake:

p.234 #683

Q: Inhibition of the kidney product renin would be expected to have which of the following outcomes?

A)increase blood pressure
B)decreae blood pressure
C)increase contractility
D)renal failure

Book says it's an INCREASE in BP. Doesn't renin increase BP, so inhibition of renin should DECREASE BP? I think I am right but I just need someone to confirm it... this stupid book goes into such in-depth analyzation of why A) is right, that I can't help but doubt myself, althought it seems pretty clear-cut.

Thanks!!

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[seraph524]

B is right.

Don't believe everything ExamKrackers says.

 

[engineeredout]

I haven't covered that topic yet in EK, but I'm wondering if its not one of those crazy negative feedback loops that EK loves to use in bio.

I don't really see how though. Can you give the explanation that EK gives?

Could it be A if since renin is blocked, the blood pressure will drop, causing a massive need of renin, and assuming the inhibitor is no longer there, renin is produced thereby raising blood pressure? I have a headache now.

 

[mytoechondriac]

B is right.

Don't believe everything ExamKrackers says.

THANK YOU!!

You are v. helpful!!

 

[seraph524]

No renin production means no active vasoconstriction, hence, low blood pressure.

And yes, I am also curious as to the answer EK gives.

 

[mytoechondriac]

I haven't covered that topic yet in EK, but I'm wondering if its not one of those crazy negative feedback loops that EK loves to use in bio.

I don't really see how though. Can you give the explanation that EK gives?

Could it be A if since renin is blocked, the blood pressure will drop, causing a massive need of renin, and assuming the inhibitor is no longer there, renin is produced thereby raising blood pressure? I have a headache now.

EK just says that A is right, and then goes into the whole renin-Angiotensin I-ACE-aldosterone cascade. It's a whole paragraph long, but it doesn't say explicitly WHY A) is the right answer. But the kicker is, it says in bold "MCAT writers frequently ask questions regarding this."

Leave it up to EK to make something simple so fcking complicated. I found at least 5 other errors in this book, so I'm pretty sure B) is right. Although what you suggest is not completely impossible...

 

[seraph524]

I still believe there is no way for the answer to be A. No weird feedback loops exists that I know of that will cause overcompensation of the renin-angiotensin cascade upon inhibition of renin production.

 

[mytoechondriac]

OK, here is what they say in the back of the book:

"A is correct. The renin-angiotensin system plays an impt role in regulating blood volume, and as a result, blood pressure: when the blood volume increases, so does the blood pressure. The kidney releases renin in response to decreased blood volume. Renin catalyzes the conversion of angiotensinI. ACE then converts ATI into ATII. ATII stimulates the adrenal cortex to release aldosterone, which in turn acts upon the kidneys to increase Na and fluid retention. This increases blood volume and blood pressure. MCAT writers frequently ask questions regarding this pathway and blood pressure."

 

[minhaj]

I am just gonna throw something out there. Lets say renin is inhibited, consequently, the blood pressure goes down. This lowering of blood pressure stimulates the release of aldosterone from the adrenal glands, which raises BP. I still believe B is the answer though.

 

[engineeredout]

From http://en.wikipedia.org/wiki/Renin-angiotensin_system

"

1. Renin cleaves an inactive peptide called angiotensinogen, converting it into angiotensin I.
2. Angiotensin I is then converted to angiotensin II by angiotensin-converting enzyme (ACE)[3] which is found mainly in lung capillaries. "

In the kidneys, it (ATII) constricts glomerular arterioles, having a greater effect on efferent arterioles than afferent. As with most other capillary beds in the body, the constriction of afferent arterioles increases the arteriolar resistance, raising systemic arterial blood pressure and decreasing the blood flow. However, the kidneys must continue to filter enough blood despite this drop in blood flow, necessitating mechanisms to keep glomerular blood pressure up. To do this, Angiotensin II constricts efferent arterioles, which forces blood to build up in the glomerulus, increasing glomerular pressure. The glomerular filtration rate (GFR) is thus maintained, and blood filtration can continue despite lowered overall kidney blood flow.



That seems to go with your answer. Decreased renin = decreased ATI = decreased ATII = not increasing blood flow = not increasing blood pressure.


Anyone have access to that ****ing board of EK errors that they make you pay for?

 

[minhaj]

OK, here is what they say in the back of the book:

Renin catalyzes the conversion of angiotensinI. ACE then converts ATI into ATII. ATII stimulates the adrenal cortex to release aldosterone, which in turn acts upon the kidneys to increase Na and fluid retention. This increases blood volume and blood pressure. MCAT writers frequently ask questions regarding this pathway and blood pressure."

The EK author is an idiot. How is renin going to catalyze the conversion of ATI if it is inhibited??? Makes no sense.

 

[engineeredout]

I am just gonna throw something out there. Lets say renin is inhibited, consequently, the blood pressure goes down. This lowering of blood pressure stimulates the release of aldosterone from the adrenal glands, which raises BP. I still believe B is the answer though.

Also from the link I posted above,

" Renin stimulates the production of angiotensin. Angiotensin causes blood vessels to constrict resulting in increased blood pressure. Angiotensin also stimulates the secretion of the hormone aldosterone from the adrenal cortex"

So it still seems that no renin = no aldosterone

 

[seraph524]

The bottom line? EK sucks. Solving the 1001 series of books won't help you for the MCAT unless you already know the material, and are just doing them for practice.

 

[engineeredout]

I still like the 1001 bio book despite some of the errors.

What if a bunch of people on the board chipped in to a common membership for that EK error board so we could share it?

 

[HawkeyePostOp]

I still like the 1001 bio book despite some of the errors.

What if a bunch of people on the board chipped in to a common membership for that EK error board so we could share it?

I second

 

[changgeon]

OK, here is what they say in the back of the book:

"A is correct. The renin-angiotensin system plays an impt role in regulating blood volume, and as a result, blood pressure: when the blood volume increases, so does the blood pressure. The kidney releases renin in response to decreased blood volume. Renin catalyzes the conversion of angiotensinI. ACE then converts ATI into ATII. ATII stimulates the adrenal cortex to release aldosterone, which in turn acts upon the kidneys to increase Na and fluid retention. This increases blood volume and blood pressure. MCAT writers frequently ask questions regarding this pathway and blood pressure."

I think the explanation is correct. however the author forgot that the question asked for the case when renin is inhibited. He just described what renin does. What renin does, he explains it well. But the author apparently didn't read the question carefully....
I have examkrackers book as well- the common mistake they make is that they don't read the questions carefully...which is... yeah. but their explanations usually seem to make sense in itself.

 

[Kaustikos]

All I know is that if ExamKrackers is right, there are going to be a lot of lawsuits filed against the makers of Tekturna and the FDA.

 

[unsung]

I still like the 1001 bio book despite some of the errors.

What if a bunch of people on the board chipped in to a common membership for that EK error board so we could share it?

That would be SWEET.

 

[unsung]

I think the explanation is correct. however the author forgot that the question asked for the case when renin is inhibited. He just described what renin does. What renin does, he explains it well. But the author apparently didn't read the question carefully....
I have examkrackers book as well- the common mistake they make is that they don't read the questions carefully...which is... yeah. but their explanations usually seem to make sense in itself.

It's probably a typo. I've noticed several Qs where the explanation is perfectly fine, but they just list the wrong letter as the correct answer. Actually in the explanation itself, sometimes they'll even explain why the letter they listed as correct is wrong. It's just a typo.

 

[Quantum Chem]

HEHe, I think I have a newer version as I looked up that question in my book and it has "a decrease in BP". That should make you feel better that you knew the answer correctly and caught it instead of agreeing with the book's answer.