Main

Why & How Plateau is Produced in Some Action Potentials? || Know the Secret Ion Channel Behind It.

📝 All topics from Membrane Potentials and Action Potential: https://www.nonstopneuron.com/post/membrane-potentials-and-action-potential 🌐 Explore our entire animation video library: https://www.nonstopneuron.com/ ● Follow me at: • Instagram: https://www.instagram.com/NonstopNeuron/ • Facebook: https://www.facebook.com/NonstopNeuron Plateau in Action Potential: the plateau is mainly produced by L type of calcium channels, that close slowly and allows the calcium entry for longer time. Chapters: 00:00 Intro 00:05 Typical Action Potential without Plateau 00:33 Plateau in Action Potential 02:02 Summary Dr Vipul Navadiya DISCLAIMER: This video is for education purposes only. Although every effort is made to ensure the accuracy of the material, viewers should refer to the appropriate regulatory body/authorized websites, guidelines, and other suitable sources of information as deemed relevant and applicable. In view of the possibility of human error or changes in medical science, any person or organization involved in the preparation of this work accepts no responsibility for any errors or omissions, or results obtained from the use of information in this video.

Nonstop Neuron

6 months ago
In this video, we will see how a plateau  is produced, in some action potential. First, let's quickly see a typical  action potential, in a neuron. The resting membrane potential, is negative. Upon stimulation, the opening of sodium  channels, leads to sodium entry into the cell. This produces an upstroke  in the action potential. Then, the opening of potassium channels,  causes the exit of potassium ions. And this produces repolarization. So this is an action potential in neurons. Now, in certa
in cells, we see a prolonged  depolarized state, called plateau. For example in cardiac muscle cells, a  0.2 to 0.3 seconds long plateau is seen. There are two factors, that play a role in this. The main reason, is L-type calcium channels. These channels are slow to  open, and slow to close. After the usual fast sodium channels have produced  upstroke, these channels open and close slowly. Because of this, the calcium ions keep  diffusing into the cell, for quite a long time. This keeps the cell
depolarized for longer. And this is seen as a plateau, in the action potential. So this is the main mechanism behind the plateau. Apart from this, the slower opening  of voltage-gated potassium channels, may also play a role. In neurons, the potassium channels open right after the upstroke. So the repolarization is quick. But the delayed opening of potassium  channels, delays the repolarization. Along with this opening of potassium channels,  the closing of sodium and calcium channels, also con
tributes to repolarization,  thus finally bringing the potential, back to negative resting membrane potential. So this is how the plateau is produced in an action potential. The benefit of the plateau, is that it causes the contraction of cardiac  muscle, to last for a longer period. In summary, the plateau is mainly produced by  L type of calcium channels, that close slowly. This allows the calcium entry for a longer time,  producing a plateau in the action potential. That's it for this video.

Related articles

Comments

@henokwg8803

👏👏👏👏👍👍👍👍👍👍your videos are the best

@Francescadbg

The reason the calcium channel is open longer is because in cardiac muscle cells, calcium needed for contraction isn’t all made in there unlike in the neuron, so the cardiac cells has to bring in some or most of the calcium needed for contractions? Am I remembering this correct?

@Ben7-qm9gb

Great

@rayan5862

The next vidéo 😅 😅 how do these ionic events actually create the familiar ECG trace? Our electrodes are attached to the patient's skin, not to the surface of their cells. How can cardiac electrical activity be measured by external electrodes?

@Ben7-qm9gb

🎉🎉🎉🎉🎉🎉