They actually start opening at the threshold potential of around -55 mV. But they open slowly. On the other hand sodium voltage gated channels also open at threshold potential but they open immediately so sodium ions start moving into the cell and they cause depolarization of the cell membrane and bring the membrane potential to about +35 mV. At about +35 mV, inactivation gates of sodium voltage gated channels close and potassium voltage gated channels which were opening slowly now finnaly fully open up and potassium ions start moving out of the cell causing the repolarization of the cell. All the stuff that I just talked about will happen exactly the same way at threshold potential but also at any potential that is more positive than the threshold potential. So if we change the membrane potential to -10 mV, which we did in this video with the voltage clamp technique, sodium channels will open immediately, potassium channels will start opening slowly, after about 1 milisecond the inactivation gates of sodium channels will close and potassium channels which were slowly opening now fully open at approximately the same moment at which the inactivation gates of sodium channels close.
@@lukakusekovic9185 Hello Luka, thanks for explaining! I was wondering, by commanding a membrane potential above the threshold, we can still have an action potential even though we are controlling the membrane potential at a specific value?
What in these data favors both an activation and inactivation gate for the Na channel, versus simply a single gate that rapidly activates then rapidly inactivates--i.e. how was it concluded that there were 2 gates instead of just one?
Could someone please explain why is it important to set a command voltage, such as keeping membrane potential at -60mv, does it show us what ionic activity there is at -60mv?
Yes, that is exactly the point. If you clamped at -60 mV, there would be hardly any additional channel openings and only a tiny amount of current would need to be injected to clamp (hold) the membrane potential at -60 mV. Now clamp to -40 mv, and many more channels, both Na and K channels would open, and more currents would have to be injected to compensate and thereby hold the potential at -40 mV.
You taught well better than my professor did! I salute you sir.
Thank you so much!! Weeks of struggle resolved in 10 min
The most useful video i have found about this topic. Thank you very much
Not fluent in english, but still understood everything. This is reallly good job! Thank you!
Thank you so much
Best demonstration! Thank you
thank you! loved the commander. haha. your video style is great! - made for real people!!!
very very wonderful video - thank you!
thank you so much !!!
Very good explanation, thank you!
Thank you!!! this video helped me so much!!!
Woah. I finally understand!!
Many thanks!
Why do the voltage-gated potassium channels open at -10mv? I don't understand this, all the textbooks say they open at around +30mv only...?
They actually start opening at the threshold potential of around -55 mV. But they open slowly. On the other hand sodium voltage gated channels also open at threshold potential but they open immediately so sodium ions start moving into the cell and they cause depolarization of the cell membrane and bring the membrane potential to about +35 mV. At about +35 mV, inactivation gates of sodium voltage gated channels close and potassium voltage gated channels which were opening slowly now finnaly fully open up and potassium ions start moving out of the cell causing the repolarization of the cell. All the stuff that I just talked about will happen exactly the same way at threshold potential but also at any potential that is more positive than the threshold potential. So if we change the membrane potential to -10 mV, which we did in this video with the voltage clamp technique, sodium channels will open immediately, potassium channels will start opening slowly, after about 1 milisecond the inactivation gates of sodium channels will close and potassium channels which were slowly opening now fully open at approximately the same moment at which the inactivation gates of sodium channels close.
@@lukakusekovic9185 Hello Luka, thanks for explaining! I was wondering, by commanding a membrane potential above the threshold, we can still have an action potential even though we are controlling the membrane potential at a specific value?
@@SukhdipKaur You can't cause an action potential because you are clamping the membrane voltage at some constant value
thanks you so much
What in these data favors both an activation and inactivation gate for the Na channel, versus simply a single gate that rapidly activates then rapidly inactivates--i.e. how was it concluded that there were 2 gates instead of just one?
its called kalium and natrium
Thank you sir.
Could someone please explain why is it important to set a command voltage, such as keeping membrane potential at -60mv, does it show us what ionic activity there is at -60mv?
Yes, that is exactly the point. If you clamped at -60 mV, there would be hardly any additional channel openings and only a tiny amount of current would need to be injected to clamp (hold) the membrane potential at -60 mV. Now clamp to -40 mv, and many more channels, both Na and K channels would open, and more currents would have to be injected to compensate and thereby hold the potential at -40 mV.
Thank you sir
what are you chompin on at the end bruh
maybe his saliva
best video..is there one for patch clamp?