Well, i have been watching you 4 years now in my medical school ( for various subjects ) and i think i finally understood what makes you a great lecturer. Its not only about the information which is clear and usually never arises some question or dilemma, it is about the way you speak. It is rhythmic, every word is clear and the breaths are rhytmic and gives you the sense of a rhytmh and harmony in your speech. Not too fast, not too slow, not fast AND slow in different times. It is steady and vivid. Thank you! You have really helped me in my exams in medical school, especially when i am doing a revising and your lectures sum up perfectly everything in only 10-20 minutes!
PHENOMENALLLLLLLLLLLL!!!!!!!!!!!! I HAVE LOOKED EVERYWHERE FOR A CLEAR EXPLANATION OF CARDIAC ACTION POTENTIAL AND BY FAR YOU WERE THE ABSOLUTE BEST!!!! THANK YOU, THANK YOU, THANK YOU SOOOOOO MUCH!
thank you again, 2 years later still revisiting your absolutely amazing explanations. i will remember you when i finish my journey and pay you back for all your help. wouldn't have made it in college or med school with you andrey, God bless!
WOW! Rarely have i seen someone explain so clearly, so cleanly and in one go! You must have needed a big glass of water after that! Thankyou for this quick review regarding cardiac action potential. I am totally subscribing to your channel!
Today while searching round this topic, I saw lot a many more videos here, but after listening u, I was provoked to hear and follow u only, I thought this was the most fruitful and informative for me, as a medical student.
This video is absolutely amazing! Such clear descriptions, not too fast... simply perfect! Thank you so so much for making this :) You are a life saver
thanks a llllottt. I have struggled for so many days about this. but this lecture is sooo good. this lecture makes me feel action potential in cardiac myocyte is like a piece of cake.
In a word... "Outstanding." Totally get rid from fear about cardiac action potential.. So confused initially about Plateau phase but now I have known that very well.. Thank you :)
u are amazing thank you i didn't think u would have a video on this, but here we are ! after hours of wasting my time on other vids i found urs. thank you a millioooon
First off I love your lectures! Also, it says on the bottom of the board that K+ has a higher outside concentration than on the inside, but you said K+ has a LOWER outside concentration compared to the inside. The ion comparison chart is a great visual to allude to for study! Keep up the great work :)
You're absolutely the best! I took my exams thanks to you! I like that you're making videos about everything and help us understand it so easy. You are the best teacher
i am taking anatomy and physiology 1 right now and i am struggling because the instructor i have doesn't explain every topic in this course very well :-( ...you do better than she does. you explain it very well
Thanks for the video. One correction: you wrote "higher potassium on the outside than on the inside" on the bottom left section of the board. Just wanted to clarify that should be switched.
thank you! when i read my textbook, i cant fully understand about this topic, i wonder why all textbooks cant explain as simple as yours, i really appreciate ur lecture, big big thanks!
initially I was wondering why this graph highly resembled an ST elevated segment of an ECG, but then came to the conclusion that it's not really related to an ECG at all, only the conductivity of cells as they depolarize through the whole muscle, THUS making the ECG readout as a PQRST - however, I can't figure out why myocytes depolarize up to 120mV, whereas ECG readouts only perceive in the 1mV range. Can someone help explain this?
Thanks for the video! I just have one question: Why is the membrane potential -90mV, when there are more positive charged ions intracellular than extracellular?
Wow, so much better than my uni lectures. Just one thing I'm confused on. At the beginning in phase 4 the myocyte had lots of K+ inside the cell, then at phase 1 the voltage gated K+ cells open (at around +30mv when Na channels close). The cell continues to repolarise by leaking K+ to the outside of the cell as the calcium channels finally close. Then it returns to phase 4, but all the K+ is now outside the cell????? Can someone point out what Im not understanding here please. At the beginning of the video in phase 4 the cell had K+ inside, yet when the cell finally returns to phase 4 it has effluxed all of its K+? Surely it should get it back and everything returns to how it was so the whole process can start again?? Thanks in advance!
Fair question! You might have already figured it out since you asked 2 months ago, but just in case! Here's what I gathered from wikipedia: Basically there are two kinds of K+ channels: rapid delayed rectifiers (IKr) and inwardly rectifying (IK1). IKr is the primary channel, so there's a net outward, positive current (making the inside of the cell more negative), and this is repolarization. IKr closes when the membrane potential is about -85 to -90 mV. BUT the IK1 keeps open throughout phase 4 (allowing K+ to return inside). The Na/Ca exchanger and Na/K pump also help to restore ion concentrations. So like, the Na/K pump is an ATPase that pumps both ions against their concentration gradient, which means it'll pump Na+ out & K+ in, thus returning everything to how it was! I actually never even questioned that part of the process so thanks for indirectly helping me learn something I needed to know!
There are several very good explanations of the Action Potential of Cardiac Muscle on you tube but none of them explain how the K+ gets back into the cell to restore to resting state. I had to spend about two days digging around the net and landed on Wikipedia as well. Not easy to understand.
Hi, great video ...but I'm a little confused. At 9.36 you say that the sodium channels are 'time dependent" , but you then immediately go on to say that they snap shut when the voltage reaches positive 30 milivolts. So is it 'time' or the voltage difference that is the determining factor as to when they snap shut? thanks
Is it because by the 'time' that the sodium channels snap shut, the influx of sodium has 'raised' the membrane potential to be 30mv as a CONSEQUENCE? (as oppossed to closing BECAUSE it has reached 30mv)
One question, why is there no Hyperpolarization phase like in Neuron action potentials? I would assume that the resting membrane potential will also be re-established due to the Na/K pump?
At this rate all k+ will be out side of cell and the ca and na will be inside. My quastion is where is the point when the k+ that efflux become influx and the Same for Na+and Ca+?
i'm confused by ur phase 4 notes. . .it says cell has higher ++ of sodium, calcium and chloride on outside, and then it says but on the other hand has a higher amount of potassium on the outside of the cell as well. so then what chemical IS on the inside of the cell during stage 4?
Best action potential explanation ever !!amazing !!!thank you so so much for making this vedio ,the entire of your vedios are really useful , they contain every infortmation we need to know ,thank you so much a gain and God bless you ......
Wonderful explanation, thank you I have question after this action potential the normal concentration of ions chnage so how return to normal.(the k more inside and the Na more outside)
Why in the whiteboard you wrote " ... it has higher outside conce. of potassium ions K+ than on the inside " for phase 4 but in the diagram you wrote it in the opposite way ???
Awesome lecture sir! But I think there is a little mistake: A cardiomyocyte actually can be stimulated either by a close cardiomyocyte or by the electrical conduction system of the heart. The nervous system (sympathetic and parasympathetic systems) cannot directly stimulate a cardiac muscle cell, they tell the SA node to slow down or speed up the pace. So, the SA node is always the pace maker. What changes the pace is the action of the autonomous nervous system on the SA node.
Sorry for all, but how this lecture can explain possibility of next cycle??? At the start of new cycle Na must be outside, K - inside. (3 sodium ions out and moves 2 potassium ions in, thus, in total, removing one positive charge carrier from the intracellular space).
OMG thank u so much go head ur amazing I could understand u clearly in all ur videos cuz I'm Arabic and all the time I need to choose videos with clear English that i could understand >>>I wish for the god the rise ur Knowlege
u told that phase 3 starts or repolarization takes place due to closing of calcium channels..........thus my question is how will these calcium channels be regulated or who will make them close at this certain point
10x a lot . The only thing which im confused with is the calcium channels, transit and long lasting cause i dont know exactly when they open i found different answers of when they open.
live for rock music Our knowledge of these concepts is continually changing as we are expanding on research. Make sure to check with the most recent sources.
how do you know all the subjects ..in detail? Like for real... how do you? This is being taught to us in 1st year of med school... how do you know all this? how many degrees did you do ?
Well, i have been watching you 4 years now in my medical school ( for various subjects ) and i think i finally understood what makes you a great lecturer. Its not only about the information which is clear and usually never arises some question or dilemma, it is about the way you speak. It is rhythmic, every word is clear and the breaths are rhytmic and gives you the sense of a rhytmh and harmony in your speech. Not too fast, not too slow, not fast AND slow in different times. It is steady and vivid. Thank you! You have really helped me in my exams in medical school, especially when i am doing a revising and your lectures sum up perfectly everything in only 10-20 minutes!
Very true !!
@@فاطمةقاسمعبدالباري syntax
Another thing I wanna add is the appropriate stress on each word Dr Prof Andrey k puts!
He's really an awesome expainer!
PHENOMENALLLLLLLLLLLL!!!!!!!!!!!! I HAVE LOOKED EVERYWHERE FOR A CLEAR EXPLANATION OF CARDIAC ACTION POTENTIAL AND BY FAR YOU WERE THE ABSOLUTE BEST!!!! THANK YOU, THANK YOU, THANK YOU SOOOOOO MUCH!
Nica Nashae Thanks! Happy to hear that :-)
thank you again, 2 years later still revisiting your absolutely amazing explanations. i will remember you when i finish my journey and pay you back for all your help. wouldn't have made it in college or med school with you andrey, God bless!
This has got to be some of the best content on youtube, I want to thank you for the effort you put into all of your videos :)
thanks Heather!
WOW! Rarely have i seen someone explain so clearly, so cleanly and in one go! You must have needed a big glass of water after that! Thankyou for this quick review regarding cardiac action potential. I am totally subscribing to your channel!
Today while searching round this topic, I saw lot a many more videos here, but after listening u, I was provoked to hear and follow u only, I thought this was the most fruitful and informative for me, as a medical student.
This video is absolutely amazing! Such clear descriptions, not too fast... simply perfect! Thank you so so much for making this :) You are a life saver
Antonia Currie Thanks for the positive comment Antonia! awesome to hear that :)
haha u just say thank u to the girls
Love you
I missed my university lecture and to learn this I decieded to watched his video. I only had to watch it ONCE it was super clear!!!!! Thank you.
I have struggled over the years to understand this thing. This is the very first time I have understood it. I can't thank you enough
Genius lecturer. Words are not enough to express gratitude, everything is on point. My favorite of all time, no doubt.
thanks a llllottt. I have struggled for so many days about this. but this lecture is sooo good. this lecture makes me feel action potential in cardiac myocyte is like a piece of cake.
Am writing exams on Monday and this video has helped me so much
Keep it up100%
the best lecturer in the world..thanks sir
In a word... "Outstanding." Totally get rid from fear about cardiac action potential.. So confused initially about Plateau phase but now I have known that very well.. Thank you :)
I’m a pharmacy student and I was struggling with this part , you dont know what you did
THANK YOU !!
u are amazing thank you i didn't think u would have a video on this, but here we are ! after hours of wasting my time on other vids i found urs. thank you a millioooon
First off I love your lectures! Also, it says on the bottom of the board that K+ has a higher outside concentration than on the inside, but you said K+ has a LOWER outside concentration compared to the inside. The ion comparison chart is a great visual to allude to for study! Keep up the great work :)
You're absolutely the best! I took my exams thanks to you! I like that you're making videos about everything and help us understand it so easy. You are the best teacher
i am taking anatomy and physiology 1 right now and i am struggling because the instructor i have doesn't explain every topic in this course very well :-( ...you do better than she does. you explain it very well
21simplelove thank you! happy to hear that :)
Hhhhhhh my doctor tried to explain that to us in 1 h 😂 and you did it just in 15 min's. Thank you ☺️
You have a really great ability in pedagogical science. Congratulations!!!
you are the reason I fell in love with biology! thank you
You are by far a better at lecturing and explaining this than my professor I'm amazed.
Thanks for the video. One correction: you wrote "higher potassium on the outside than on the inside" on the bottom left section of the board. Just wanted to clarify that should be switched.
I really love your pronounciation, body language and explanation.
Attractive.
Brazillian youths would say, "When I grow up, I want to be like you" thanks a lot.
the best class ever i have. it clears lots of my chilly doubts. thank u sir
Wish I had stumbled upon this video long ago! Super helpful and easy to follow. Thank you!!
Best ever video about cardiac action potential 💖
thank you! when i read my textbook, i cant fully understand about this topic, i wonder why all textbooks cant explain as simple as yours, i really appreciate ur lecture, big big thanks!
I love you man you're always so clear and on point.
I paused the video to give this man a break.
initially I was wondering why this graph highly resembled an ST elevated segment of an ECG, but then came to the conclusion that it's not really related to an ECG at all, only the conductivity of cells as they depolarize through the whole muscle, THUS making the ECG readout as a PQRST - however, I can't figure out why myocytes depolarize up to 120mV, whereas ECG readouts only perceive in the 1mV range. Can someone help explain this?
I'm watching this in 2020...thank you so much for this perfect explanation🖤🧡you help me a lot
It's 2024 and you still watch his contents... Thank you ❤
Crystal clear. Thank you. You are the best.
finally i did understand how this action potential works, Thanks, but what about T-type calcium channel?
Thanks for the video! I just have one question: Why is the membrane potential -90mV, when there are more positive charged ions intracellular than extracellular?
Because potassium leaks out from ICF to ECF
Well done! Very clear explanation for all five phases. Thanks.
Wow, so much better than my uni lectures.
Just one thing I'm confused on. At the beginning in phase 4 the myocyte had lots of K+ inside the cell, then at phase 1 the voltage gated K+ cells open (at around +30mv when Na channels close).
The cell continues to repolarise by leaking K+ to the outside of the cell as the calcium channels finally close. Then it returns to phase 4, but all the K+ is now outside the cell?????
Can someone point out what Im not understanding here please. At the beginning of the video in phase 4 the cell had K+ inside, yet when the cell finally returns to phase 4 it has effluxed all of its K+?
Surely it should get it back and everything returns to how it was so the whole process can start again??
Thanks in advance!
Fair question! You might have already figured it out since you asked 2 months ago, but just in case! Here's what I gathered from wikipedia:
Basically there are two kinds of K+ channels: rapid delayed rectifiers (IKr) and inwardly rectifying (IK1).
IKr is the primary channel, so there's a net outward, positive current (making the inside of the cell more negative), and this is repolarization. IKr closes when the membrane potential is about -85 to -90 mV.
BUT the IK1 keeps open throughout phase 4 (allowing K+ to return inside).
The Na/Ca exchanger and Na/K pump also help to restore ion concentrations. So like, the Na/K pump is an ATPase that pumps both ions against their concentration gradient, which means it'll pump Na+ out & K+ in, thus returning everything to how it was!
I actually never even questioned that part of the process so thanks for indirectly helping me learn something I needed to know!
There are several very good explanations of the Action Potential of Cardiac Muscle on you tube but none of them explain how the K+ gets back into the cell to restore to resting state. I had to spend about two days digging around the net and landed on Wikipedia as well. Not easy to understand.
Hi, great video ...but I'm a little confused. At 9.36 you say that the sodium channels are 'time dependent" , but you then immediately go on to say that they snap shut when the voltage reaches positive 30 milivolts. So is it 'time' or the voltage difference that is the determining factor as to when they snap shut? thanks
Is it because by the 'time' that the sodium channels snap shut, the influx of sodium has 'raised' the membrane potential to be 30mv as a CONSEQUENCE? (as oppossed to closing BECAUSE it has reached 30mv)
One question, why is there no Hyperpolarization phase like in Neuron action potentials?
I would assume that the resting membrane potential will also be re-established due to the Na/K pump?
forever herie but this is about cardiac muscle cells
those are not pacemaker cells
The greatest lecturer.
Start at 5:15 if you just want a (detailed) audio review of the phases.
this video is one of my best thank u so much u have saved my life
At this rate all k+ will be out side of cell and the ca and na will be inside.
My quastion is where is the point when the k+ that efflux become influx and the Same for Na+and Ca+?
Thanks very much great job with nice pronouncation,that every foreign doctors can understand you!! Really very nice👍👍👍
i'm confused by ur phase 4 notes. . .it says cell has higher ++ of sodium, calcium and chloride on outside, and then it says but on the other hand has a higher amount of potassium on the outside of the cell as well.
so then what chemical IS on the inside of the cell during stage 4?
Unbelievable video- best explanation I've ever watched!
+Carley Garantziotis thanks!
Thank you so much for such crystal clear explanation!!
One word awesomeee bravo fantastic oh sorry one word cannot explain ur beautiful teaching style thanks alot
Best action potential explanation ever !!amazing !!!thank you so so much for making this vedio ,the entire of your vedios are really useful , they contain every infortmation we need to know ,thank you so much a gain and God bless you ......
Wonderful explanation, thank you
I have question after this action potential the normal concentration of ions chnage so how return to normal.(the k more inside and the Na more outside)
My favorite RUclips teacher!!!!!🙌
* phase 4 i think there is a typo on your notes under phase 4 vs the diagram regarding the concentration?
THANKS TO YOU - I WILL GET AN A ON MY EKG EXAM!!
This was amazing, thank you so much. As a visual learner, I benefited a lot.
yep I'd agree with Nica Nashae. Best I have found
I understand things only with your explanation .. thank you soooo much
♥♥
زينب عبد الكريم You're very welcome! :-)
Why in the whiteboard you wrote " ... it has higher outside conce. of potassium ions K+ than on the inside " for phase 4 but in the diagram you wrote it in the opposite way ???
type error
Sir you are amazing
Every thing is understood
Mind blowing
God bless you
Seriously some hero just have RUclips channel 💕💕💕🙆🙆
Awesome lecture sir!
But I think there is a little mistake:
A cardiomyocyte actually can be stimulated either by a close cardiomyocyte or by the electrical conduction system of the heart.
The nervous system (sympathetic and parasympathetic systems) cannot directly stimulate a cardiac muscle cell, they tell the SA node to slow down or speed up the pace.
So, the SA node is always the pace maker. What changes the pace is the action of the autonomous nervous system on the SA node.
Sorry for all, but how this lecture can explain possibility of next cycle??? At the start of new cycle Na must be outside, K - inside. (3 sodium ions out and moves 2 potassium ions in, thus, in total, removing one positive charge carrier from the intracellular space).
Thanks a lot for such a clear explanation
OMG thank u so much go head ur amazing I could understand u clearly in all ur videos cuz I'm Arabic and all the time I need to choose videos with clear English that i could understand >>>I wish for the god the rise ur Knowlege
best video on cardiac action potential thank u sir
Excellent!
very helpful... thank you for your time
Allah's blessings be upon you
you are just fantastic. Thank you!
u told that phase 3 starts or repolarization takes place due to closing of calcium channels..........thus my question is how will these calcium channels be regulated or who will make them close at this certain point
You saved me!!! Thank you so much.
You are amazing, simple as that.
thank you so much for this great lecture and explanation
Awesome stuff. Thank you so much for making this video and so many other great ones!
thank you, keep up with the great job. I ALWAYS KNOW that I will find the info that I need in your videos .:)
best teacher in the world thinx very much
love your videos! they help a lot thanks
Thank you so much this explanation is just perfect🤍🤍
I wish you were my teacher! Great Stuff
This is just really really amazing
:)
Thanks for that
:)
Thank you very much Sir you are such the best lecturer ever..
really!?that's it! , i really regret it that i didnt watch this video before, thank you
the best video I ever seen
As always , perfect time utilization 😊😊
what about the t type calcium channels?
Thank you so much sir
U really made it crystal clear
U r awesome😃👍
10x a lot . The only thing which im confused with is the calcium channels, transit and long lasting cause i dont know exactly when they open i found different answers of when they open.
live for rock music Our knowledge of these concepts is continually changing as we are expanding on research. Make sure to check with the most recent sources.
Ok thank you
awesome video sir.... thank you for clearing my doubts!!!!
this is the BESTvideo.bless you!
this is amazing amazing amazing amazing! Thank you so much
U r an amazing teacher, thank u so much, love from pakistan ❤️
great video great explanation.....Thank you
Thank you very much for your useful videos ..you have helped me a lot
What’s his reference book?
Thanks a lot , this lecture was really helpful
how do you know all the subjects ..in detail? Like for real... how do you? This is being taught to us in 1st year of med school... how do you know all this? how many degrees did you do ?
Ak Lecture thanks for your help 💓🌸
During hypercalcemia, does bradycardia occur?