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- 1 Untitled
- 2 Citations needed?
- 3 Context
- 4 Reorganizing the field of MEMBRANE POTENTIALS
- 5 Reorganizing the field of MEMBRANE POTENTIALS-2
- 6 physiological?
- 7 Negativity of the resting potential
- 8 Much to wordy
- 9 Tags
- 10 Millman Eq. appears to be wrong in this page
- 11 Regulation?
- 12 Basic Questions
- 13 Proposed external link
- 14 Assessment comment
Could someone put in the values for the permeabilities in a typical cell? like calculate how the Nernst equals -70mV at rest? 22.214.171.124 21:37, 19 June 2007 (UTC)
For such a long text on such a science-heavy subject, it has very few citations? I feel there are a lot of facts in there which it wouldn't hurt to give sources for. For instance, why is the resting potential pegged at -70 mV? Who measured that? --Miturian (talk) 09:48, 9 January 2014 (UTC)
Could someone please extend the first sentence to include something like "...is a term in [whatever] biology" so that people like me, using "random article" to check stuff, know in what context this term is used? Is tis molecular or cell biology? Tierlieb 19:48, 2 November 2007 (UTC)
Reorganizing the field of MEMBRANE POTENTIALS
There are three articles now which discuss very much the same things with numerous repetitions and description of the same material in different terms.
As it was already suggested by Methoxyroxy 12:37, 2 November 2006 (UTC), it needs a really big clean-up and optimization. There is a lot of confusion there so I will do this albeit not at once. I will move different parts between these three articles, edit and unify their style etc. At later stage I will need someone who is native English speaker to do spellcheck.Rvfrolov (talk) 20:52, 2 January 2009 (UTC)
Reorganizing the field of MEMBRANE POTENTIALS-2
You are right. Worse, there is no mention here of potassium leak channels, the ones that set the resting potentials. Uniporters are oddly credited? —Preceding unsigned comment added by Cagedcalcium (talk • contribs) 01:11, 11 September 2009 (UTC)
- Experimental studies of dissociated cells or brain slices (usually from rats) are often conducted at temperatures below normal body temp. That's probably what "physiological temperature" is supposed to mean here. It's easier to maintain a healthy preparation at those temperatures. I agree that this should be clarified, but this article is a bit too technical for me to work on. Looie496 (talk) 19:00, 27 April 2009 (UTC)
Negativity of the resting potential
The article does not explain why the resting potential is negative despite both media having zero global charge. Which I believe is due to negative charged proteins inside (although I don't understand how does this not violate zero global charge). It also does not mention that the membrane potential is given by Vm = Vin - Vout. Rend (talk) 20:06, 18 March 2010 (UTC)
- This seems to be one of those pages that is chronically in need of work. I agree with you that an improved "measuring" section would do well to mention in-minus-out (although that's true for any membrane potential, not just at rest). The answer to the first part of your question is selective permeability, so K+ leaves the cell, leaving impermeant anions (including but not limited to proteins) behind. The page sort of addresses this, but obviously not very well. --Tryptofish (talk) 21:14, 18 March 2010 (UTC)
- Yes, the article does at least try to explain why the resting potential is negative -- it's a consequence of the Goldman equation. The reason the article does not mention that Vm = Vin - Vout is because I thought it wouldn't be helpful. Every measured voltage is actually a voltage difference, so to explain what Vin and Vout are, you have to bring in the concept of a voltage reference point. Thus Vin and Vout are each, when properly understood, actually more complicated than Vm is. Maybe the concept needs to be explained anyway, but my first intuition was that it would be best to gloss over the issue. Regards, Looie496 (talk) 01:21, 19 March 2010 (UTC)
Much to wordy
This article is not very reader friendly. I made just one simple change, but it is only one of many needed. The article is much too wordy. I understand that the average person will not be able to understand the article. However, keep in mind that many beginning students will come to this page seeking help. It should be ESPECIALLY for them. That's the purpose of wiki; its not a platform to pontificate. I suggest going through this and making similar changes as I did, ionic species-simplified as ions. Seriously? —Preceding unsigned comment added by 126.96.36.199 (talk) 07:14, 19 March 2011 (UTC)
I am going to remove the "lead too long" and "refimprove" tags added to this article today. The lead is not overly long given the length of the article, and the need for references doesn't require a tag to be noticed. There is no doubt that this is a pretty low-quality article which needs improvement in numerous ways, but defacing it with big ugly tags at the top doesn't promote that, in my opinion. Looie496 (talk) 17:08, 19 March 2011 (UTC)
Millman Eq. appears to be wrong in this page
I think ion permeabilities in Millman equation should be replaced by conductances. Ref: Ove Sten-Knudsen, "Biological membranes: theory of transport, potentials and electric impulses", Cambridge University Press, 2002, p. 382 — Preceding unsigned comment added by Hamid.mirzaei (talk • contribs) 18:25, 12 December 2011 (UTC)
- If you are confident about that, please feel free to fix it. If you have difficulties with formatting, I can probably help with that. Regards, Looie496 (talk) 18:54, 12 December 2011 (UTC)
An essential point is missing: Is Na+/K+-ATPase working until ATP is exhausted? Or until there is no Na+ or K+ to be pumped? Probably there is some sort of negative feedback. But how can cAMP measure the Membrane potential, because it is no Transmembrane protein ? The negative feedback should be slow enough (T > 10 ms) not to prevent the emergence of the Action potential. Who knows a correct answer? --188.8.131.52 (talk) 17:36, 6 March 2012 (UTC)
- I don't think this page says anything like that about cAMP. What happens is that there is a steady state between the effects of the ATPase and the opposing effects of leakage channels (principally K+). Nothing is really depleted. --Tryptofish (talk) 01:37, 7 March 2012 (UTC)
- "there is no actual measurable charge excess in either side. That occurs because the effect of charge on electrochemical potential is hugely greater than the effect of concentration so an undetectable change in concentration creates a great change on electric potential."
Can this sentence be clarified, specifically:
the effect of charge on electrochemical potential significantly larger then the effect of charge on concentration - is this a general statement or true in all cases?
And if charge is more significant then concentration in influencing electrochemical potential why does a small change in concentration greatly effect electropotential? Or does it mean electrochemical potential? Either way how does it make any sense, is it correct or nonsense and what is the exact meaning behind the message?
I am a beginning student trying to wrap my head around the fundamentals of membrane potential physiology. A couple of other questions I have:
1) What is the reason Na+ stays at its location right across the barrier on the extracellular side of the membrane? Diffusion? Electrochemical potential? Electric Charge repulsion?
2) If the answer is the electrochemical gradient/potential, because it is trying to move to a "less" positive potential.. if its located extracellularlly isn't that the "great unknown" where any molecules/cells/protein etc. are able to float by and possibly influence it? What happens if one of these has a "LESS" positive potential then the membrane that Na+ is currently attracted?
3) Can someone explain why can't Na+ be used for the entire process to establish the same voltage interactions leading from resting to action potential (as long as thier was less concentration intracellularly... if it is about LESS positivity ..Or vice versa for K+?)? — Preceding unsigned comment added by Trancelot (talk • contribs)
- Regarding the first question, the basic fact is that electrical forces are so strong that even a tiny excess of charged particles creates a huge electromotive force -- that's a general principle. Regarding the rest, can I suggest that you take a look at the membrane potential article? It's written in a quasi-tutorial way, and serves as background for our other articles about cellular electrical activity. Regards, Looie496 (talk) 17:15, 17 January 2013 (UTC)
Some time ago I wrote an interactive tutorial on the origin of the resting membrane potential which is available on my university website: http://www.st-andrews.ac.uk/~wjh/neurotut/mempot.html I have received some positive (unsolicited) feedback from a number of neuroscience students and staff in various other institutions, and I think it answers some of the questions raised on this talk page. I'm therefore minded to put a link to it in the "External links" section of the article. But I wrote it, and I don't want to contravene vanity publishing guidelines, so I thought I'd put it here for a while and see if there were any strong opinions against doing this. Wjheitler (talk) 20:05, 27 September 2013 (UTC)
- I think it's great, but it might make more sense to add a link from the membrane potential article rather than from here. That's really the "base" article for all aspects of this topic, and it seems like your tutorial would be helpful in understanding it. Looie496 (talk) 22:21, 27 September 2013 (UTC)
The comment(s) below were originally left at several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section., and are posted here for posterity. Following
|Rated "high" for consistency with action potential. Article needs references/sources. - tameeria 00:37, 19 February 2007 (UTC)|
Last edited at 00:37, 19 February 2007 (UTC). Substituted at 04:11, 30 April 2016 (UTC)