June-Max
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According to FA small fibers are blocked faster than large fibers and myelinated fibers faster than unmyelinated. But here is a question:
During a visit to the dentist’s office, a 17-year-old girl is given an injection of lidocaine in her mouth for a local procedure. Which of the following correctly demonstrates the order in which the nerve fibers are affected by lidocaine (from first to last)?
A. Large myelinated nerve fibers > large unmyelinated nerve fibers >
small myelinated nerve fibers > small unmyelinated nerve fibers
B. Large unmyelinated nerve fibers > small myelinated nerve fibers > large
unmyelinated nerve fibers > small unmyelinated nerve fibers
C. Large unmyelinated nerve fibers > small unmyelinated nerve fibers > large
myelinated nerve fibers > small myelinated nerve fibers
D. Small myelinated nerve fibers > large myelinated nerve fibers > small
unmyelinated nerve fibers > large myelinated nerve fibers
E. Small unmyelinated nerve fibers > small myelinated nerve fibers > large
unmyelinated nerve fibers > large myelinated nerve fibers
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| fox
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looks like A
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| Leopard
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Correct answer is E
Best of luck
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| fox
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Well i based my answer on june max's explanation from first aid! Now leopard (anti first aid) seems to have a different view. I'll look up which one's right & get back.
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| klimt
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it's E
FA also says that overall, size factor predominates over myelination.
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| fox
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Ok so its E then? But why large unmyelinated > large myleinated?
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| Leopard
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There is no such generation of fibers which can be labelled as "Large unmyelinated"
There are three categories of fibers
- A
- B
- C
C fibers are the smallest and Unmyelinated while B and A type are myelinated and of various sizes.B is small but of bigger size than C fibers
The local anesthetics affect them in the order
C>B>A
Best of luck
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| young_doc
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Answer is D.
Size is the first most important thing, and as FA mentions, small fibers are more susceptible. So that leaves us with answers D & E.
E is definitely wrong, because myelinated fibers are more susceptible than unmyelinated ones.
And if you have doubts about D, then check out the discussion portion of this paper:
"large myelinated axons were substantially more susceptible to lidocaine than small unmyelinated axons"
http://www.anesthesia-analgesia.org/cgi/content/f...
=)
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| Leopard
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Authority speaks
Review of Medical physiology by Ganong : Edition 22 page 61
Attached Files:
Susceptibility of Nerves.pdf (40 KB, 11 downloads)
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| young_doc
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Well after looking into it further, i find A LOT more research papers that say myelinated is more susceptible than un-myelinated.
And i trust research papers more than textbooks. (textbooks often contain mistakes)
My 2 cents, and i stand by D!!!
Gluck to you!
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| Leopard
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Hahahahahahaha = Funny
Textbooks are wrong and www.blablablabla is right
May God bless all of us
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| mediocre
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| young_doc
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Leopard wrote:Hahahahahahaha = Funny Textbooks are wrong and www.blablablabla is right May God bless all of us
Leopard,
You're meaningless and senseless bashing is not necessary on this forum. And it is most definitely not professional behavior.
Everyone on this forum, including myself, has the right to express their opinions, regardless of whether you agree with them or not.
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| mediocre
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whatever the ans might b..........
"I've made the most important discovery of my life. It's only in the mysterious equation of love that any logical reasons can be found". ~ John Forbes Nash, in A Beautiful Mind
TK
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| Leopard
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young_doc wrote:
Leopard,
You're meaningless and senseless bashing is not necessary on this forum. And it is most definitely not professional behavior.
Everyone on this forum, including myself, has the right to express their opinions, regardless of whether you agree with them or not.
Do not be upset please ,that was just a surprise on anyone who says that "Ganong" is wrong.Don't you think that it is really funny and worth laughing.
Best of luck
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| young_doc
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"Beware of too much laughter, as it deadens the mind and produces oblivion" - The Talmud
After 7 editions, there are still mistakes in Big Robbin's!
So no i personally don't think it's very funny.
But i'm glad you had a good laugh. And i was just joking with the quote. In fact:
"Laughter is the closest distance between 2 people" - Victor Borge
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| mediocre
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doods ,both of u (leopard and young doc) are great minds ,and we r proud 2 have you up in the forum,saves us lesser mortals a lot of time finding ans
I request you guys/gals or (guy n gal??) to express ur views without commenting on the other .we all can be right and we all can be wrong aswell ,it is accepting your drawbacks that makes you a greater person,and helps you in the xam aswell!!(no one except God is perfect.)
Let us benifit from this forum ,and help others without making it an arguing ground......thanx(0n behalf of the forum members,although I am not d moderator!! )
Please xcuse me for sidetracking the main issue ,but i hope this helps all of us,
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| young_doc
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Sorry mediocre.
I just take it to heart when someone else's post puts me down. Let's ALL try to be more supportive of each other.
It is possible to correct without critisizing.
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| Leopard
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young_doc wrote:"Beware of too much laughter, as it deadens the mind and produces oblivion" - The Talmud After 7 editions, there are still mistakes in Big Robbin's! So no i personally don't think it's very funny. But i'm glad you had a good laugh. And i was just joking with the quote. In fact: "Laughter is the closest distance between 2 people" - Victor Borge 
Dear Young doc
I do not know what should I say.You said "after 7th eddition" there are mistakes.It means you find these mistakes in 8th edition which unfortunately does not exist yet.7th edition is the latest edition which was out in 2004.
Best of luck
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| mediocre
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Blessed are they who have the gift of making friends, for it is one of God's best gifts. It involves many things, but above all, the power of going out of one's self and appreciating whatever is noble and loving in another
Thomas Hughes
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