jena99 wrote:
Action potential of a ventrivular fiber
phase 1 : voltage gated K channels begin to open(FA)
Phase 2: plateau --- Ca influx balance K efflux
Phase 3: rapid repolarization------massive K efflux due to opening of voltage gated K channels
So, when does the voltage gated K channel close? Plateau? And this channel keep opening on phase 0,1,3,4? On the KLN, “the channel begin to reopen during the latter part of the plateau phase”, but on the FA, “voltage gated K channels begin to open during phase 1”. I got confused. Which one is correct?
Dear
Do not strain on the K-channels much because these are of different types and open at different time.
Best of luck
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| new_n_lost
Politically InCorrect
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Eagle_303 wrote:jena99 wrote:
Action potential of a ventrivular fiber
phase 1 : voltage gated K channels begin to open(FA)
Phase 2: plateau --- Ca influx balance K efflux
Phase 3: rapid repolarization------massive K efflux due to opening of voltage gated K channels
So, when does the voltage gated K channel close? Plateau? And this channel keep opening on phase 0,1,3,4? On the KLN, “the channel begin to reopen during the latter part of the plateau phase”, but on the FA, “voltage gated K channels begin to open during phase 1”. I got confused. Which one is correct?
Dear Do not strain on the K-channels much because these are of different types and open at different time. Best of luck
Excuse me can you give reference to that statement
Thankyou
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| Dr_C
Forum Newbie
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jenna, there are different type of K channels but do remember K voltage gated channels do close in phase 0 which is depolarization phase, but about the ungated K channels they are always open and you will always have an efflux of K.
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| mjbapana
Forum Senior
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Posts: 152
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in cardiac muscle u have 2 types of voltage gated k channels.
1)inward rectifying (iK1): these are open under resting conditions that is before phase 0 and depolarization signals the beginning of their closure. so the begin to close at the beginning of pahse 0 and finish closing at phase 1. and ostart to open in end of phase 4.
2)Delayed rectifying channels(iK) opens with depolarization and closes when repolarized{this part even i have'nt understood but this what kaplan book says.but in the video he says that they begin to open in phase 3 to start repolariztion and close by phase 4 and are responsible for relative refractory period.
but i hope in the exam they never ask aQ about this b'coz each source says differently and they are so many of them channels. but i'm going by what dr kudrath said in the video it makes the most sense. but i think that the way he talks he could convince anyone that the moon was really made of cheese!!!!!
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