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Overdrive suppression requires that the fastest pacemaker cell delivers Na+ to the secondary pacemaker cell. While secondary pacemaker makes Na/K pump over drive to hyper polarize
Yes. That's what. It is mentioned in the video. The hyperactive Na+/K+ pump, leading to hyperpolarization of the latent pacemaker. Anyway, shall try to add further molecular mechanisms in the subsequent videos. Thanks Regards,
Yes and no. No because , Purkinje fiber is not a naturally autorhythmic fiber. It does not show pacemaker potential under normal circumstances (which is there only in SA node and AV node). So no question of causing suppression of its pacemaker potential. But yes, because, if for some reason, in abnormal condition, if Purkinje fiber were to develop the pacemaker potential, then, yes , SA node CAN suppress it as its rate of firing is much higher .
Very well explained...I got it.... But,I think Hyperactive Na/K pump is not enough for this 20-30 sec delay...when SA node stops firing or there's block in transmission.....Is not so? ....There must be some other mechanism involved in this,too.....
When AV node has also got the property of autorhythmicity, and an AP similar to SA node, then why doesn't it immediately become pacemaker, when SA node fails? It has to come out of some sort of inhibition, in order to start its own spontaneous depolarizations.
SA node and AV node both show autorhythmicity. Both have similar APs generated by similar ionic currents. And yet, SA node is the pacemaker. Why? It's because SA node recover earliest from every excitation. And why does it recover fastest? It's because it's K+ current is faster. AV nodal K+ current is little slower to cause recovery from each excitation.
There are many. I mostly refer to these 3 - Boron & Boulpaep, Berne & Levy, and Ganong. However, I take the facts, and try to provide my conceptual inputs, to make it a more wholesome understanding of the subject.
Absolute legend. Great explanation. I'm interested in exactly *how long* it takes for the AV node to get out of overdrive suppression. Is it something to do with the difference in depolarization rates between the SA and AV nodes? Like the higher that hyperpolarized state from the baseline, the longer it takes to adjust to that natural baseline depolarization rate?
Czech me out, Babe Yes. That’s right. More the extent of hyperpolarization, more time the AV node takes to come out of the ‘suppression’. The slow down of the Na+/K+-pump activity needs 15-20 seconds (after SA node has stopped discharging impulses). Another 5-10 seconds for the AV node to completely regain its automaticity. Thus, 30 seconds is said to be the time. More than this time will push toward Stokes-Adams syndrome. (The difference in the rates of depolarization matters, as it is the ionic changes during depolarization that are being settled by the activity of Na+/K+-pump, as a process of recharging.)
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Can't have word to explain my feelings after this explanation
I was so confused in getting this,you explained it like no one else did,thank you so much😍😍
sairamuqaddas khan Thanks for the comment..!
Best Teacher Explaining concept
Super explanation, nothing more is required!
Thanks!
Great explanation sir🙏
Great job 👍
It was reaally nice sir.
Now i come to know the cause of stroke adam syndrome in type 3 heart block.
Thanks sir.
Great
Very helpful!
Overdrive suppression requires that the fastest pacemaker cell delivers Na+ to the secondary pacemaker cell. While secondary pacemaker makes Na/K pump over drive to hyper polarize
Yes. That's what. It is mentioned in the video. The hyperactive Na+/K+ pump, leading to hyperpolarization of the latent pacemaker.
Anyway, shall try to add further molecular mechanisms in the subsequent videos.
Thanks
Regards,
Thank you.. so explaining this concept..
Excellent
Thanks for the comment,
Regards,
Thanks a lot, very helpful explaination.. Is the same concept applied on Purkinje fibers?
Yes and no.
No because , Purkinje fiber is not a naturally autorhythmic fiber. It does not show pacemaker potential under normal circumstances (which is there only in SA node and AV node). So no question of causing suppression of its pacemaker potential. But yes, because, if for some reason, in abnormal condition, if Purkinje fiber were to develop the pacemaker potential, then, yes , SA node CAN suppress it as its rate of firing is much higher .
Thanks for the explanation!
Amazing explanation! thank you sir!
Thanks !
Very well explained...I got it.... But,I think Hyperactive Na/K pump is not enough for this 20-30 sec delay...when SA node stops firing or there's block in transmission.....Is not so? ....There must be some other mechanism involved in this,too.....
When AV node has also got the property of autorhythmicity, and an AP similar to SA node, then why doesn't it immediately become pacemaker, when SA node fails? It has to come out of some sort of inhibition, in order to start its own spontaneous depolarizations.
SA node and AV node both show autorhythmicity. Both have similar APs generated by similar ionic currents. And yet, SA node is the pacemaker. Why? It's because SA node recover earliest from every excitation. And why does it recover fastest? It's because it's K+ current is faster. AV nodal K+ current is little slower to cause recovery from each excitation.
Thanks
Welcome….!
Thankyou so mch 🙂💕
Ty
Sir
As a physiologist i have the curiosity to know your book of reference
There are many. I mostly refer to these 3 - Boron & Boulpaep, Berne & Levy, and Ganong. However, I take the facts, and try to provide my conceptual inputs, to make it a more wholesome understanding of the subject.
Thank you sir
He did not explain the molecular mechanism of overdrive suppression.. Disappointed :(
Can you elaborate on it? What was expected in the molecular mechanism? I'll make one more video to incorporate that part.
Absolute legend. Great explanation. I'm interested in exactly *how long* it takes for the AV node to get out of overdrive suppression. Is it something to do with the difference in depolarization rates between the SA and AV nodes? Like the higher that hyperpolarized state from the baseline, the longer it takes to adjust to that natural baseline depolarization rate?
Czech me out, Babe Yes. That’s right. More the extent of hyperpolarization, more time the AV node takes to come out of the ‘suppression’. The slow down of the Na+/K+-pump activity needs 15-20 seconds (after SA node has stopped discharging impulses). Another 5-10 seconds for the AV node to completely regain its automaticity. Thus, 30 seconds is said to be the time. More than this time will push toward Stokes-Adams syndrome. (The difference in the rates of depolarization matters, as it is the ionic changes during depolarization that are being settled by the activity of Na+/K+-pump, as a process of recharging.)
@@VivekSirsPhysiology Thank you very much for elaborating; it all makes complete sense now.