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Urgent NBME 13 41 - trickemcy
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03-06-2012, 02:39 PM
The tracing shows contractile responses of a skeletal muscle prep to electrical stimulation at five different frequencies. the amount of Ca sequestration in the sarcoplasmic reticulum is highest during which of the following labeled responses?
A B C D or E cant post picture, some who has written the nbme please... i choose E which was wrong
03-06-2012, 02:43 PM
I chose E for this too.
I think the answer might be A, that one had the highest frequency of electrical stimulation. But it doesnt make sense, because higher stimulation would cause increased calcium release from the sarcoplasmic reticulum leading to depleted calcium inside of it right?
06-03-2012, 06:03 PM
If you look at the tension curve you see that in the lower frequencies you have an up and down curve, indicating contraction and relaxation. In the higher frequencies you see a prolonged contraction, indicating tetany.
So in order for you to have a quick contraction, relaxation, contraction sequence, you have to sequester calcium at a much faster rate. If you are in tetany like at the higher frequencies, then you have a large amount of calcium in the cytosol prolonging the contraction.
11-13-2012, 02:25 AM
The Answer is AAAAAAAAAA
i got this right and i use some printscreen software taken pictures of my final answers of this block while i was doing online edition and also i didnt see this question in my wrong Qs so im pretty sure the answer is A and this explantion made by FUB got this wrong!!! what i thought was when contracting the Calcium is releasing from sarcoplasmic reticulum to the cytoplasm (and i think uw has one Question asking about cytoplasm here) so the less contract the more calcium is left in the SR correct me if my explanation is wrong, good luck
11-09-2013, 08:44 PM
Ya, it was actually asking the amount of calcium in SARCOPLASMIC RETICULUM, not in cytoplasm.
So it is actually asking which stimulus producing least contraction. I got fooled as well. |
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