Action Potential - Firing of a Neuron - Depolarization

In this video, Dr. Kushner breaks down an action potential, a brief electrical charge that travels down the axon of a neuron. Consider the different phases to this amazing event:
1. Depolarization (sodium channels open - Na+ rushes in - neuron become more positive - generates an action potential - +30 mV)
2. Repolarization (sodium channels close; potassium channels open - K+ rushes out; neuron rebalances voltage)
3. Hyperpolarization/Refractory period (neuron recharges; -90 mV)
5. Resting potential/state (neuron returns to -70 mV)

[@harrisonbogursky6535]

wow you deserve the Nobel prize for most clear understanding of an action potential.

[@PsychExplained]

Much appreciated 🏆 😀

[@_K.L]

OMG SALTY BANANA!!!!!!!!!!!!!!!!!!!!!!!!!! I literally constantly forget what’s high on the inside and what’s high on the outside. Now I’ll never forget. Thank you!

[@PsychExplained]

It’s all about the mnemonics 😊

[@_K.L]

@PsychExplained You're doing the LLOYDS work! Keep it up! Looking forward to watching more videos.

[@alyagha5600]

geniunely this is the best video I've seen on action potential. You made it so simple and I really appreciate that.

[@avadf8127]

rightttttt

[@PsychExplained]

Wow, thanks! 🙏🏻

[@mjob450]

OMG!!! thanks very much for this! I have never commented on any video on KZbin....but i think this video triggers me, it's well explained. THANK AGAIN!!

[@lukes5102]

In physio psychology introductory class best explanation I have ever seen

[@dakshatakamble5591]

After years of reading AP over and and over, watching multiple videos, making notes for 1000th time.. this video finally taught AP without having to mug up😭😭🙌🏼🙌🏼

[@PsychExplained]

Happy to help 🤓

[@imel_diary]

The best video i have seen so far on action potential thank you so much.

[@PsychExplained]

Too kind. Glad it helped 🧠

[@mariettevanjaarsveld4006]

This video is life-changing 😊! Thanks so much for the detailed drawing and steps!

[@PsychExplained]

So happy to help!

[@occam3064]

Yo I don't know if you still make videos but keep it up! I'm taking AP Psychology right now and you have hands down the clearest and most thorough explanations I have seen yet. It hits that sweet spot between simple to understand and complex enough to contain all necessary detail. Thank you and I would really appreciate if you were to post more.

[@PsychExplained]

Appreciate the kind words! It may surprise you but I teach high school AP Psychology. These videos are for you, and helping you earn that 5! Many more to come.

[@elaf1553]

@@PsychExplained 😊

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This video just made me get fired up for my test ❤️🔥🔥🔥 thank you 🙏🏾

[@PsychExplained]

Love the pun!! Good luck 👍

[@syedajiniya5050]

Love this Doc!

[@PsychExplained]

Appreciate the message 😇

[@tylerlupercio256]

Amazing Teacher, honestly not only did I learn more about Neurons but I also learned how to teach in a more clear fashion by watching how you explain things

[@PsychExplained]

Thank you so much for your kind words!

[@rebecamendoza2017]

wow I was so confused on action potential and you made it so clear and understanding without using so much terminology! Thank you!!!!!!!!!!!

[@PsychExplained]

You're very welcome!

[@factuna6694]

Thank you for the very well put explanation. The only thing, however, you didn't mention was the sodium-potassium pump, which is what allows the neuron to return to the resting stage after being hyperpolarized!

[@PsychExplained]

Wonderful! Great pick up

[@musselchee9560]

Fantastique! = +-+-+-+-+-+- ... I recently learned that due to a violent upbringing I have premature myelination and four other premature stuff that went on at a microscopic level within me. I was left with axons looking as if they were pumped up on steroids due to development adaptation. This vid has just given the nitty gritty to my external potential. Look out bad world, the Hulk lives. THANK YOU Doc.

[@virtue1495]

Your energy is everything and so are your teaching skills! God bless you! Thanks a lot. Doing my nursing degree and needed to understand this well!! Everything you said helped a lot🙏🏾💕

[@PsychExplained]

Wonderful! Nurses are amazing. Enjoy the journey :)

[@annemeluch2276]

Again thanks so much for the detailed yet not overcomplicated explanations. The visuals really help me relate math and science together something I normally struggle with a lot.

[@user-qt2pi6bw4b]

Thank you for explaining it to me in simple and understandable way

[@PsychExplained]

Glad it was helpful!

[@jiujitsujudy]

I have been trying to understand AP for a year and I finally do now thanks to this video!!! Thank you!!!

[@PsychExplained]

That’s so great to hear! Happy to help 😊

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Fantastic explanation!

[@Aboutdorna]

I love the way that you explain things ! a person who even dose not have science background can totally understand it and that is amazing ! keep spoiling us with your videos

[@PsychExplained]

Happy to help! 😎😎

[@stephanieknapaysweet7852]

😀 Thank you so much for the step by step. I went through so many videos and your video was awesome. Very detailed step by step.

[@actuallynur]

THANK YOU FOR EVEEEERYTHING.I’m so happy that I found this channel.Please keep going 🫶🏼

[@annemeluch2276]

agreed

[@leonandresvalderramarico4449]

You are teaching me also English! Keep going men. Please more on statistics (null hypothesis, regressions) and physiology (muscle function, muscle damage).

[@PsychExplained]

More to come!

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This is so well made

[@zareenaanowar9415]

confused myself over the slides for an hour and learned in your video within 12 mins. nice job mahn

[@PsychExplained]

This is awesome to hear 😎

[@JC-hu2nw]

Excellent ! Thank you for your clear, clear, and easy explanation. A BIG THANK YOU!

[@PsychExplained]

Glad it was helpful!

[@peipewde6988]

thankx finally somone explained what cause the hypopolarization .

[@jungandrea6060]

Oh my gosh! Thank you! I finally understand the concept!!!

[@PsychExplained]

So glad to hear! I love those “ah-ha” learning moments :)

[@roenschultz]

BEST EXPLANATION!! 🙏🏼❤

[@PsychExplained]

Glad it was helpful!

[@calisthenicsindia8498]

Thank you so much

[@user-qq7jk7dy9h]

This makes so much more sense now! Thank you! I am taking psychopharmacology and sometimes the readings just blur together. The visuals and concepts used (salty banana and toilet refractory phase) just helps tremendously! I am now a forever subscriber!! Thank you- I will watch all your videos

[@PsychExplained]

Wonderful! Thank you for the kind words. Happy learning 🧠 📚 ✏️

[@motivatemejas8118]

Your video in 1.25 speed was the best explanation of this process! Thank you

[@PsychExplained]

Glad it was helpful!

[@zorodzaichari8811]

Wow the explanation is top notch 👌 thank you good teacher

[@PsychExplained]

Thank you! 😃

[@YollyM-to4hg]

Thank you very much, this is the best video and I now understand the action potential

[@PsychExplained]

You are welcome!🙏🏻

[@paulagar9140]

Love love love your explanations! Thankyou

[@PsychExplained]

You are so welcome!

[@nikhilrai2151]

beter than 2 hrs lecture of my teacher

[@PsychExplained]

Glad to hear!

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Wow!! I love the way you teach. Thank you so much for making this seem so easily to understand. I subscribed to your channel.

[@PsychExplained]

Thanks for subbing!

[@FerryDzaack]

I went over this topic in my psychology book over and over and over and jus couldn't get it. 12minutes after watching this and I finally understood!! thank you so much

[@PsychExplained]

Excellent!

[@ameliatahnia]

Thank you so much for this video! It was super helpful and the explanation was so clear. I hope you keep doing these educational videos :)

[@PsychExplained]

Thank you for the support!

[@tiyahirani4995]

This video has helped me so much with biology, thank you so much, such great help!

[@PsychExplained]

Wonderful!!

[@lukes5102]

Amazing video thank you so much!

[@PsychExplained]

You're so welcome!

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Wow you explained that so well! Thank you!!

[@PsychExplained]

Thank you for watching!

[@msjay5747]

THE ABSOLUTE ABSOLUTE ABSOLUTE ABSOLUTE best explanation

[@PsychExplained]

Happy to help 😎

[@croys8608]

Thanks! At last, I'm beginning to understand the process

[@PsychExplained]

Glad it helped!

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This is so good!

[@PsychExplained]

Thank you for the kind words!

[@IvanaBudisin]

Amazing! Thank you

[@PsychExplained]

My pleasure!

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[@PsychExplained]

Wow, thank you!

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Excellent

[@lb4660]

Best explanation 😊

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Thank you

[@future-psych]

Thank you so much! Definitely a huge help!

[@PsychExplained]

Wonderful to hear!

[@ramithadewadassanayake7100]

Easy to understand - Great

[@PsychExplained]

Glad you think so!

[@enasmohamed9183]

Thanks you You made this easy . First time to understand it

[@PsychExplained]

Glad it helped!

[@ptphysio3046]

Well Explained thank you very much

[@emaaneemaane7emaaneemaane7]

Really well explained 👍

[@PsychExplained]

Thank you 🙂

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Thank you so much sir. This is so helpful and clear🙏

[@PsychExplained]

You are most welcome

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[@PsychExplained]

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[@PsychExplained]

You're so welcome!

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Amazing

[@daisymarquez7668]

Taught me more than my professor in this video!! Thank you. Please more videos on nervous system or endocrine

[@PsychExplained]

Will do!

[@daisymarquez7668]

@@PsychExplained just finished endocrine. Thank you anyway! any videos on the cardiovascular or skeletal muscle?

[@PsychExplained]

@@daisymarquez7668 check out Siebert Science! He has great videos on these topics.

[@daisymarquez7668]

@@PsychExplained okay thank you!!

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Your explanation more clearly than my prof 😭 thank you , bless you teacher

[@PsychExplained]

Happy to help! 😇

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[@PsychExplained]

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[@PsychExplained]

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[@PsychExplained]

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[@PsychExplained]

Most welcome

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Thank u soooo match 🩷

[@PsychExplained]

Welcome 😊

[@ifranadeem]

Whatt a great explanation finally i understand action potential just one question that in the end after hyperpolarisation do the sodium ions also go back out of the neuron??

[@meeromeer8812]

Thanks.

[@PsychExplained]

You're welcome

[@angelinawilson6498]

You real for this

[@deepalipimpale309]

Please make videos on sensation and perception.

[@chancelira6302]

Your drawing got way better

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This is genius !!

[@shariqanida9492]

🎯 Key Takeaways for quick navigation: 00:31 *🧠 Understanding Action Potential* - Action potential defined as a brief electrical charge traveling down a neuron. - Neuron anatomy overview: soma, dendrites, axon, axon terminal. - Importance of action potential in neuron communication. 02:23 *🧪 Ion Concentration and Neuronal Resting State* - Neurons surrounded by ions: sodium and potassium. - Resting potential of a neuron at -70 millivolts. - Explanation of the "salty banana" memory technique. 04:01 *⚡️ Excitation and Binding of Neurotransmitters* - Excitation of neurons by stimuli like neurotransmitters. - Role of acetylcholine in binding to receptor sites on dendrites. - Opening of channels for sodium influx upon binding. 06:05 *🎇 Threshold and Action Potential Initiation* - Explanation of the neuron's firing threshold at -55 millivolts. - All-or-none principle: neuron fires when threshold reached. - Activation of voltage-gated sodium channels for action potential initiation. 07:54 *🔥 Depolarization Phase* - Depolarization: neuron becoming more positive. - Sodium influx leading to increased positivity inside the neuron. - Voltage change triggers the action potential. 10:04 *⏳ Repolarization and Hyperpolarization* - Repolarization phase: closure of sodium channels, opening of potassium channels. - Potassium efflux causing the neuron to return to negative polarity. - Hyperpolarization and refractory period before returning to resting potential. Made with HARPA AI

[@newmoonrain]

Why is the voltage at -70 inside at the start? If potassium is positive, what else is in the neuron that's so negative? Great video btw, thank you!

[@PsychExplained]

The resting membrane potential of approximately -70 millivolts (mV) inside a neuron at rest is primarily due to the differential distribution of ions across the cell membrane, particularly potassium (K+) and sodium (Na+), as well as the selective permeability of the membrane to these ions.

[@terry-annhall2704]

Sir yor explanation of the action potential was very good, but you did not explain how the amount of sodium on the outside and potassium on the inside return to normal.

[@PsychExplained]

Repolarization - brings the cell back to resting potential. The inactivation gates of the sodium channels close, stopping the inward rush of positive ions. At the same time, the potassium channels open.

[@fazelahmad7320]

Thanks, good explination! But what happens afterward because this time all the K+ is outside and Na+ is inside. The normal position was the opposite (K+ were inside and Na+ were outside).

[@jk9-fr6xm]

asking the same question

[@PsychExplained]

Potassium channels open in response to depolarization, allowing potassium ions to move out of the cell down their concentration gradient. This efflux of potassium ions helps restore the negative charge inside the cell. Sodium channels that opened during depolarization begin to close, reducing the influx of sodium ions into the cell. This decreases the positive charge inside the cell. As a result of these processes, the ion gradients across the cell membrane gradually return to their resting state, with potassium ions predominantly inside the cell and sodium ions predominantly outside. This restoration of ion gradients allows the neuron to prepare for subsequent action potentials and maintain its resting membrane potential.

[@faba-carter3996]

Cool

[@pawloiox2585]

So, the transmission of the action potential is like an electric canon

[@qismatunnisabrohi693]

❤

[@emaaneemaane7emaaneemaane7]

Sir you explained really well but Kindly tell me why chloride ions didn't play that much role in action potential though they are also present in this process? kindly Explain.

[@PsychExplained]

They play a major role at the synaptic bulb (axon terminal). I will touch on this more in my next video on neural transmission ⚡️⚡️⚡️⚡️⚡️

[@sophiasanderson]

thank you lord for this video. everyone else just rushes through it

[@PsychExplained]

So glad it helped!

[@chancelira6302]

DR.KUSH

[@LemlemKinde]

you are so unique please keep it up but i have a question why the + and _ charge interchange and where is the _ charge comes ? both K+ and Na+ are positive how exchange meaning when Na + inter the k+ out HOW ??? i public health student and i want to be know more about this

[@PsychExplained]

Hello! Not sure I understand your question - In the case of the sodium-potassium pump, which is essential for maintaining the resting membrane potential of nerve cells and muscle cells, sodium ions (Na+) are pumped out of the cell while potassium ions (K+) are pumped into the cell.

[@user-dh8ci9ue5w]

And how does the potassium come back in and the sodium leave to go back to original resting potential? That bit wasn't mentioned. It sounds like in the end, the charge might be the same, but with hardly any K+ And lots of Na+ compared to first charge

[@PsychExplained]

While the sodium-potassium pump helps restore the original ion concentrations, other mechanisms, such as the closing of voltage-gated sodium channels and the opening of potassium leak channels, also contribute to reestablishing the resting membrane potential.

[@aryangoswami7512]

How you get awareness out of this unconscious matter ?

[@Nadavsolution]

How don't we have only Na+ inside after several times the nerve is in action? Should be nun out of K+ and only have Na+ left inside the neurone??

[@user-ik8rv2dj8j]

진짜 잘가르치네....기말시험 구세주

[@SanKosar2005]

Is the Refractory period part of the repolorization?

[@PsychExplained]

Great question. I would say no. These are separate events. Order: Resting state --depolarization-Repolarization --hyperpolarization (refractory period). Repolarization is part of the firing process of a neuron, while the refractory period deals with a neurons ability to generate another action potential.

[@ramithadewadassanayake7100]

Hi Do you have lecture for ECG basics?

[@PsychExplained]

I don’t sorry. Closest thing is talking about EEG in my sleep video 😴

[@drkdrk7]

Not bad, but i think u didn't say main point. How can an electrical potential be created if both potassium and sodium have a positive charge? Where does the negative charge come from inside the cell?

[@PsychExplained]

I feel like you asked me which came first: chicken 🐔 or the egg 🥚?

[@jeremiahsmarketing]

I too like this guy...What...salty Bannna!....😂😂😂

[@maiditahiri9942]

Salty banana was pure genius 🤣

[@GuidetteExpert]

I dont think its right to put only minus or positive inside the neuron, there is both positive and negative always outside and inside the neuron. Just the amount changees.

[@PsychExplained]

This is correct 👍

[@sirbucket3202]

these sodium ions are going in and out of the neurons so fast is this Tom and Jerry or something😭

[@jaguar.ssingh3295]

LEEGGGGEEENNNDDDD

[@Papa_and_son2024]

Tell me the story of the trojan horse again.. You sound like you're teaching history.

[@PsychExplained]

Your brain has been evolving for millions of years, so in some ways, yes I am teaching history 🧠