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  #1  
Old 02-25-2012
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Arrow NBME 5 Block 4 discussion

Q15:
Ok I know that the receptor will bind to DNA but it will also bind the steroid hormone. The way I know it is that the receptor has a distinctive binding to the hormone which causes a conformational change then allowing the receptor to bind to DNA. So the receptor by itself should specifically bind to the steroid hormone.


Q18:
explanation please


Q19:
Explanation please


Q 23:
I think the answer is D. Carotid receptors increase firing when PO2 is low. As seen in the normal diagram when inspired O2 concentration is low the minute respiration is high due to carotid body response. But when you remove these receptors then there shouldn't be a response to low O2 levels at all.


Q27:
explanation please


Q30:
I think the answer is C. In the stem its given that its a cyst. CA125 would be for a tumor not a cyst. The most common cyst is a follicular cyst which can cause increased estrogen production. So checking estradiol levels should be more important in this case.


Q46:
No idea how to figure out the answer. Really need an explanation for this one.
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Old 02-25-2012
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Qs 15 ... Zinc fingers on steroid receptor is a DNA binding site Motif on transcription factors .. see pg no 72 of kaplan 2009 edition , gene expression chapter

Qs 18 If you look at the lung it shows multiple openings or gaps its very similar to an elastase enzyme dissolving the lung tissue its emphysema ..thus A ... just type emphysema gross images and you will see large number of similar images

Qs 19 ... its accumulation of metabolic products like lactic acid , ADP which stimulate the pain receptors ... see below


http://www.healthinplainenglish.com/...tack/index.htm

http://www.cingulate.ibms.sinica.edu...20ischemia.pdf


http://www.sciencedirect.com/science...02870335903131


Qs 23 yes even i feel the ans is D

Qs 27 Qs In Nephrogenic DM after water is withheld ... still there is no absorption of water so the plasma osmolarity stays high as water is lost ,serum Na also stays high ... so A and B is ruled out , urine has less salt and more water so osmolarity is low and ADH is increased as pituitary is normal secreting ADH in response to high Na level ...

Qs 30 CA 125 will determine if its CA or not , hence dictates futher management ,

Qs 46 i feel the ans is D 2 litres , see the graph in FA pg no 505 , FRC after normal expiration is at the center so here the center is at 2 L ...

hey need help with ...Qs 12 dont they measure LH surge to check for ovulation ??

qs 14 doesnot oxytocin work with estrogen in breast development ?

Qs 33 ?? cystitis ?? Qs 35 ?? C???

Qs 39 ??
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Quote:
Originally Posted by Hitman View Post
Qs 46 i feel the ans is D 2 litres , see the graph in FA pg no 505 , FRC after normal expiration is at the center so here the center is at 2 L ...
I agree, the answer is 2. At FRC there should be equal and opposite pressure pressure from both sides. In this case at 2L, the lung is +10 and the chest is -10. Trans organ pressure comes out to 0, which is the case at FRC


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hey need help with ...Qs 12 dont they measure LH surge to check for ovulation ??
The luteal phase begins 24-36 hrs before ovulation, so progesterone starts getting produced before ovulation. So if you look at the menstrual cycle chart in FA you will see that right before ovulation all other values are decreasing or have already decreased to low levels. Progesterone is the only that starts increased right before ovulation and then continues to keep increasing.


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qs 14 doesnot oxytocin work with estrogen in breast development ?
HPL and estrogen are responsible for development of breast tissue. Development is the key word here.

Prolactin is important for milk production after birth.

Oxytocin is ONLY responsible for milk let down. To get it from the lobules where they are produced to the nipple.


Quote:
Originally Posted by Hitman View Post
Qs 33 ?? cystitis ?? Qs 35 ?? C???
Q33:
has contracted Gonorrhea. You have to associated STDs more with reproductive organ infections in both sexes rather than urinary, bladder infections. In the female will cause PID and in the male will cause epididymitis. You also know the other things it does, arthritis, fitz-hugh curtis.

Q35:
Gastrin stimulates acid production. No matter where the gastrin comes from it acts on the parietal cells to cause acid production. More gastrin means more acid production. Especially in cases like this (ie. zollinger ellison) there willl be ulcers due to marked production of acid by gastrin.


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Qs 39 ??
I think its D, don't agree with the Key. Obviously we have to identify the Typ II cells. I've always thought them to be smaller and flatter than type I. So it looks like its D to me, unless its a trick here.???
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Qs 35 ..In FA a flow chart on Pg 319 says the most imp mechanism by gastrin to stimulate acid production is by stimulating ECL ... so i thought that would be the ans ...

Qs 39 ... type 2 cell are longer and cuboidal type , C is the ans look at this link

http://www.bluegrass.kctcs.edu/Natur...iratory_System
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Qs 35 ..In FA a flow chart on Pg 319 says the most imp mechanism by gastrin to stimulate acid production is by stimulating ECL ... so i thought that would be the ans ...[/url]
Look at the picture of the gastric parietal cell in FA.

Gastrin works directly on the CCKb receptor on the gastric parietal cell. It also acts on the ECL cell to cause Histamine release, although this is a secondary affect. Primary affect is always on the parietal cell.
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hmm , yes its parietal cell , should have kept it simple

thanks ...
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Old 02-27-2012
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Q1: according to FA p.258, aortic regurg is heard on the left sternal border, not the right sternal border as is in the question stem :/

Q2: that looks nothing like the 'saw-tooth' ECG in FA p.263

Q5: explanation please.

Q7: shouldn't it be E? isnt it the vascular smooth muscle that is acting on by bronchodialators?

Q15: shouldn't it be E? isnt the receptor itself DNA, not binds DNA.

Q16: explanation please.

Q23: explanation please. i put B.

Q33: why not B?

Q39: can somebody label all the parts? i thought the answer here was A... but then again maybe those are macrophages?

Q46: explanation please.
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Qs 1 yes thats correct , but a murmur will also be heard near the aortic valve also ... there are many clues for you to diagnoses AR so , its a little tricky for location but not wrong

Qs 2 well its the best ECG for sawtooth better than FA , google for better ones

Qs 5 no blood so no shigella and campylobacter , cereus occurs in hours and resolves itself in a day , cryptosporidium in HIV so Giardia .. ortherwise the history is typical for giardia

Qs 7 hey it dilates bronchioles , not a vasodilator

Qs 15 ... Zinc fingers on steroid receptor is a DNA binding site Motif on transcription factors .. see pg no 72 of kaplan 2009 edition , gene expression chapter
Qs 16 all chambers enlarged and died of CHF .. its DCm

Qs 23 Carotid receptors increase firing when PO2 is low. As seen in the normal diagram when inspired O2 concentration is low the minute respiration is high due to carotid body response. But when you remove these receptors then there shouldn't be a response to low O2 levels at all.

Q33:
has contracted Gonorrhea. You have to associated STDs more with reproductive organ infections in both sexes rather than urinary, bladder infections. In the female will cause PID and in the male will cause epididymitis. You also know the other things it does, arthritis, fitz-hugh curtis.

Qs 39 see below , i have given a link

Qs 46 i feel the ans is D 2 litres , see the graph in FA pg no 505 , FRC after normal expiration is at the center so here the center is at 2 L ...
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Quote:
Originally Posted by Hitman View Post
Qs 1 yes thats correct , but a murmur will also be heard near the aortic valve also ... there are many clues for you to diagnoses AR so , its a little tricky for location but not wrong

Qs 2 well its the best ECG for sawtooth better than FA , google for better ones

Qs 5 no blood so no shigella and campylobacter , cereus occurs in hours and resolves itself in a day , cryptosporidium in HIV so Giardia .. ortherwise the history is typical for giardia

Qs 7 hey it dilates bronchioles , not a vasodilator

Qs 15 ... Zinc fingers on steroid receptor is a DNA binding site Motif on transcription factors .. see pg no 72 of kaplan 2009 edition , gene expression chapter
Qs 16 all chambers enlarged and died of CHF .. its DCm

Qs 23 Carotid receptors increase firing when PO2 is low. As seen in the normal diagram when inspired O2 concentration is low the minute respiration is high due to carotid body response. But when you remove these receptors then there shouldn't be a response to low O2 levels at all.

Q33:
has contracted Gonorrhea. You have to associated STDs more with reproductive organ infections in both sexes rather than urinary, bladder infections. In the female will cause PID and in the male will cause epididymitis. You also know the other things it does, arthritis, fitz-hugh curtis.

Qs 39 see below , i have given a link

Qs 46 i feel the ans is D 2 litres , see the graph in FA pg no 505 , FRC after normal expiration is at the center so here the center is at 2 L ...
thank you!
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Old 03-18-2012
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thanks ver useful
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Old 06-24-2012
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Please can someone explain?

Q32: How can constriction of precapillary sphincter increase lymph flow? wouldn't the decreased capillary hydrostatic pressure decrease trasudation from capillary?
Why not increase capillary permeability, since the ques says that protein content of lymph does not change along with increased flow?

Thanks in advance.
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Old 06-27-2012
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Quote:
Originally Posted by drssbaz View Post
Please can someone explain?

Q32: How can constriction of precapillary sphincter increase lymph flow? wouldn't the decreased capillary hydrostatic pressure decrease trasudation from capillary?
Why not increase capillary permeability, since the ques says that protein content of lymph does not change along with increased flow?

Thanks in advance.
The answer is B. increased capillary hydrostatic pressure.

increased capillary permeability is not an option. Moreover, increased permaebility means proteins would also be flitered out so that would change the pretein composition on lymph
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Q13 i thought the answer was E. i mean what about the escape from aldosterone mechanism?? Would there be an increased ANP release in response to fluid overload leading to natriuresis and hence extracellular fluid should be deleted. i thought so

Q39 is this labelled correctly?
A alveolar macrophage
B pulomnary blood vessel???
C Type II pneumocyte
D Type I pneumocyte
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39- yup thats right...

13- in conns there is only mild increase in ser Na which is attributed to aldosterone escape but i think the ecf will increase..
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