ACTION POTENTIALS: Depolarization and repolarization on an axon, Includes All or nothing principle

Watch this video for help undertading what an action potential is and how it is generated. I explain what the all-or-nothing principle and refractory period are and why both are important for survival. This links to AQA A-level topic 6.
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Пікірлер: 86

  • @aaminahthekilla
    @aaminahthekilla Жыл бұрын

    i swear it gets so hard to pay attention and understand things in class because of the amount of information thats constantly thrown at me, and the way they make things more complicated than they actually are - but your videos are so straightforward it takes a lot of the pressure away! thank you so much!! :)

  • @shazmeertv44

    @shazmeertv44

    Ай бұрын

    Nobody asked

  • @laithjadallah6061
    @laithjadallah60613 жыл бұрын

    you are an amazing person. you are honestly going to help me achieve a good grade with your explanations and simple diagrams. Im gonna cry i swear thank you so much

  • @MissEstruchBiology

    @MissEstruchBiology

    3 жыл бұрын

    Aww thank you. I'm so pleased the videos have helped you understand and have given you confidence. Good luck with your studies!

  • @alaamorad8687
    @alaamorad86872 жыл бұрын

    you have saved my life in this topic you don't know how much I have struggled I got my teacher to explain this topic about five times and I also got a tutor for it but that also didn't work out thank you so much for everything you are amazing with you nice and simple explanations and the diagrams are also amazing thank you again

  • @MissEstruchBiology

    @MissEstruchBiology

    2 жыл бұрын

    Ahh amazing!!! It is such a tough topic and it took me a while to get my head around it when I first learnt it and then again when I first had to teach it so I am really pleased that you found it understandable the way I explained it :D

  • @aflan8109
    @aflan81093 жыл бұрын

    Thank you so so much for this video, it was explained so clearly I understood it the first time!

  • @MissEstruchBiology

    @MissEstruchBiology

    3 жыл бұрын

    Hello, It is a tough topic so I'm really glad you found my explanation clear enough ☺

  • @saminaamin6808
    @saminaamin680811 ай бұрын

    Omg you've made topics so easy for us !! I wonder what would have i done if your videos weren't here... THANKYOU SO MUCH LOVE❤ I don't know how to thank you🥺🥺❣️

  • @MissEstruchBiology

    @MissEstruchBiology

    11 ай бұрын

    I'm so pleased!!! So happy it had helped you to understand it 😊😊

  • @sumayabusur7034
    @sumayabusur70343 жыл бұрын

    Thank you so much for your amazing explanation it really helped me

  • @MissEstruchBiology

    @MissEstruchBiology

    3 жыл бұрын

    Hi Sumaya, I'm really glad it helped! :)

  • @ethancheung114
    @ethancheung1143 ай бұрын

    so much clearer than a text book or my lecturer. thank you

  • @MissEstruchBiology

    @MissEstruchBiology

    3 ай бұрын

    yay so pleased 😁😁

  • @dilprotiva2992
    @dilprotiva29922 жыл бұрын

    You always have the answer to my confusion😫😫 I love you miss❤❤Never stop with your work👍👍

  • @MissEstruchBiology

    @MissEstruchBiology

    2 жыл бұрын

    I'm so please the video helped you to understand the topic!! :D

  • @imaanmudassar5181
    @imaanmudassar51812 жыл бұрын

    Thank you so much! your video helped me tons:)

  • @MissEstruchBiology

    @MissEstruchBiology

    2 жыл бұрын

    aww I'm so pleased you've found them helpful ☺

  • @simdicool5438
    @simdicool54383 жыл бұрын

    Your videos are honestly SO HELPFUL thanks so much

  • @MissEstruchBiology

    @MissEstruchBiology

    3 жыл бұрын

    Glad you like them!

  • @keb7686
    @keb76862 жыл бұрын

    You’re legend !! I’m subscribing now

  • @MissEstruchBiology

    @MissEstruchBiology

    2 жыл бұрын

    aww thank you and welcome ☺

  • @ramrad5905
    @ramrad5905 Жыл бұрын

    U explain perfect,thank u so much

  • @MissEstruchBiology

    @MissEstruchBiology

    Жыл бұрын

    thank you!!!!

  • @anthonyyau9315
    @anthonyyau9315 Жыл бұрын

    This video is a masterpiece

  • @MissEstruchBiology

    @MissEstruchBiology

    Жыл бұрын

    oh wow thank you!

  • @reemamin1584
    @reemamin15846 ай бұрын

    hi miss Estruch , could you please make a video about the scientific article ( ial edexel oct/nov exam) and your expectations 😘

  • @adamrose6809
    @adamrose68093 жыл бұрын

    Loving the videos miss, hope you had a nice Christmas. Just a question, what’s the point of having unmyelinated neurones then if the myelinated ones are much faster?

  • @MissEstruchBiology

    @MissEstruchBiology

    3 жыл бұрын

    Thank you 😊 Hardly any are unmyelinated, but this site goes through why some are www.ncbi.nlm.nih.gov/books/NBK554461/

  • @Sanchoo25
    @Sanchoo252 жыл бұрын

    This is good ...thanks am subscribing right now

  • @MissEstruchBiology

    @MissEstruchBiology

    2 жыл бұрын

    Thanks for the sub! So glad that you like the video. I hope the others help you too!

  • @daaragoodluck
    @daaragoodluck3 жыл бұрын

    I’ve said this before imma say it again you are a God Send! Awesome vid as usual 💥

  • @MissEstruchBiology

    @MissEstruchBiology

    3 жыл бұрын

    Aww thank you so much 😊

  • @missgirl7879
    @missgirl78795 ай бұрын

    I think im gona cry, hate biology so much. Been blank and sleepy past couple of lessons uderstanding nothing and u literally summarised it to a level my brain could comprehended 😭😭 this whole channel... thank u so much fr

  • @MissEstruchBiology

    @MissEstruchBiology

    5 ай бұрын

    Oh no, sorry you have been finding it so hard. I hope my videos can make you start to enjoy the subject again 😊

  • @shuaybhussein8282
    @shuaybhussein82822 жыл бұрын

    These are sooooo good

  • @MissEstruchBiology

    @MissEstruchBiology

    2 жыл бұрын

    Thank you so much ☺ So glad you found it helpful

  • @gamingspotlight6194
    @gamingspotlight61943 жыл бұрын

    Your definitely a god send when it comes to a level biology !! I’m not sure if it’s covered in your spec but do you know what happens when drugs block the gated potassium channels in the axon membrane ? Like how it would affect the action potential trace

  • @MissEstruchBiology

    @MissEstruchBiology

    3 жыл бұрын

    Hello, This could be an application question on the specification, where you would be given information to use to work out the outcome. Drugs tend to affect the synapses rather than axon, as this is where neurotransmitters (chemicals) diffuse. Some drugs prevent the neurotransmitter from detaching from the receptor and some can bind and block the receptor. So this can result in either the action potential continuously being triggered without any stimulus and this can cause muscles to remain contracting where as others, like pain killers, that block there receptors prevent the action potential travelling further and therefore preventing a response or preventing the action potential travelling the the CNS. Hope that helps.

  • @gamingspotlight6194

    @gamingspotlight6194

    3 жыл бұрын

    @@MissEstruchBiology Hi miss, thanks a lot for your detailed reply. I'm still confused about what happens when drugs block the gated potassium channels in the axon membrane and how it would affect the action potential trace

  • @gamingspotlight6194

    @gamingspotlight6194

    3 жыл бұрын

    @@MissEstruchBiology I've written down that it slows down the action potential since K+ channels are blocked but that's it :(

  • @khaled-ig1hz
    @khaled-ig1hz2 жыл бұрын

    hi, Mrs @9.25 in the refractory period how does the axon ensure that the impulse is unidirectional and so prevents the backflow of the impulse where there is a more negative charge so surely the Na+ ions are attracted to the opposite charge? I'm confused how its kept 1 way thank you !

  • @MissEstruchBiology

    @MissEstruchBiology

    2 жыл бұрын

    Hello, This is because the ions can only pass through the voltage gated protein channels, so at that point the gates are closed. Hope that helps 😊

  • @markdean6174
    @markdean61743 жыл бұрын

    Hi really good video. Do we need to know about what determines the speed of action potentials and the difference between non-myelinated and myelinated neurones for aqa? Thanks

  • @MissEstruchBiology

    @MissEstruchBiology

    3 жыл бұрын

    Hello, Yes you do need to know that. I thought I'd made a video on this already, but doesn't seem so.

  • @markdean6174

    @markdean6174

    3 жыл бұрын

    @@MissEstruchBiology thats fine i just wasnt sure

  • @raisadrawss4190
    @raisadrawss4190 Жыл бұрын

    you're a lifesaver

  • @MissEstruchBiology

    @MissEstruchBiology

    Жыл бұрын

    Happy to help ☺️

  • @rocksyantonygnaneswaran8595
    @rocksyantonygnaneswaran8595 Жыл бұрын

    What's the difference between a generator potential and an action potential?

  • @galefray
    @galefray2 жыл бұрын

    Hi Miss Estruch, really awesome video as always. I was just curious however; are the K+ channel proteins which open and close also voltage-gated like the Na+ ones? Thanks so so much

  • @MissEstruchBiology

    @MissEstruchBiology

    2 жыл бұрын

    Hello, Some of them are where as some a permanently open, which is one of the reason why the membrane is more permeable to K+

  • @MatT-vf7qo
    @MatT-vf7qo3 жыл бұрын

    at repolarisation, does the na+/k+ pump and Na+ ion channel close

  • @MissEstruchBiology

    @MissEstruchBiology

    3 жыл бұрын

    As this is a movement is due to active transport, this pump is constantly in action, as long as it has energy for the active transport to occur.

  • @benstorey8085
    @benstorey8085 Жыл бұрын

    Hi miss, I’m a bit confused on how it triggers the next impulse along the neurone. In one book it’s saying sodium diffuses sideways but in the other it’s saying it makes localised currents so it can jump from node to node

  • @phoebemay7550

    @phoebemay7550

    Жыл бұрын

    Hi its a bit late but isn't that the difference between myelinated and non-myelinated neurones? I think in myelinated neurones the impulse 'jumps' whereas in non-myelinated neurones the sodium diffuses sideways in the wave of depolarisation?

  • @benstorey8085

    @benstorey8085

    Жыл бұрын

    @@phoebemay7550 nah in this book was saying that sodium diffuses sideways but then can only make the action potentials In the breaks of the myelin

  • @marcocasali8434
    @marcocasali84342 жыл бұрын

    Hi. How is a potassium concentration gradient created. Potassium is constantly being diffused out of the axon

  • @ItsTheEddemundos

    @ItsTheEddemundos

    2 жыл бұрын

    inside of axon is negative so K+ wants to diffuse in (down electrochemical gradient) - it also wants to diffuse out as conc. of K+ is higher inside axon (down conc. gradent). Equilibrium is reached at -70mV so there is no net movement of K+ at that point (resting potential).

  • @curtishagen6840
    @curtishagen68402 жыл бұрын

    Hi, I wonder if you can help me, I bought a second hand Action Potential Stimulation) Therapy machine - MK 1.1 but I don’t know how to used it. Please can you advice me where to get instructions Manual book or website were I can download video . Thanks

  • @MissEstruchBiology

    @MissEstruchBiology

    2 жыл бұрын

    Hello, Oo afraid I can't help on that. I've never used one. Sorry!

  • @mxrcy03
    @mxrcy032 жыл бұрын

    Hi Miss, does this video explain how the action potential passes along the UNmyeliated axon?

  • @MissEstruchBiology

    @MissEstruchBiology

    2 жыл бұрын

    Hello, this would be the case for both. I have another video - factors affecting the speed of conductance, which goes through unmyelinated v myelinated too.

  • @salenaakram2436
    @salenaakram24362 жыл бұрын

    I love you, Miss Estruch.

  • @MissEstruchBiology

    @MissEstruchBiology

    2 жыл бұрын

    I hope the video helps your studies 😀

  • @tahakarim1901
    @tahakarim19014 ай бұрын

    I wanted to ask, how does the refractory period ensure that the action potential only travels in one direction? I was a bit confused on this.

  • @ashmartyr6392

    @ashmartyr6392

    2 ай бұрын

    The refractory period stops the action potential from generating another one in the backwards direction (Mexican wave) because the refractory period causes that part of the axon that has just fired an action potential to be unresponsive as voltage-gated channels are closed. This means the next action potential can’t trigger another action potential backwards as it is unresponsive. This only allows the action potential to travel unidirectionally from the dendrite to the axon terminal :)

  • @user-tz5pz8ev7u
    @user-tz5pz8ev7u3 жыл бұрын

    can Na+ travel both ways through the channel? I thought that Na+ can only move into the axon and not move the other way.

  • @MissEstruchBiology

    @MissEstruchBiology

    3 жыл бұрын

    Hello, If you have a look at the image on this link it may help.en.m.wikipedia.org/wiki/Resting_potential Na+ moves out due to the Na+/K+ pump, but then diffuses back into the axon through the Na+ channel. So it does travel both ways, but through different proteins. Hope that helps ☺

  • @Mozzie7920
    @Mozzie79203 жыл бұрын

    Wait so how does the refractory period ensure they travel in one direction?

  • @MissEstruchBiology

    @MissEstruchBiology

    3 жыл бұрын

    Because at -80mV a lot of Na+ is needed to trigger an action potential, whereas the next part of the axon moving forward will be in the -70mV resting potential and therefore as Na+ enters the axon this part will meet the threshold and cause the action potential to continue to move forwards in one direction along the axon. Hope that helps

  • @juliettecurran3173
    @juliettecurran31732 жыл бұрын

    Hi I was just wondering if you're allowed to refer to sodium as Na+ and potassium as K+ in the exam?

  • @Caller8194

    @Caller8194

    Жыл бұрын

    in the exam refer to them as sodium IONS. IONS you must says ions

  • @jafwonta

    @jafwonta

    Жыл бұрын

    @@Caller8194 Na+ ions?

  • @Caller8194

    @Caller8194

    Жыл бұрын

    @@jafwonta Na+ is already an ion. Saying Na+ ions is like saying Na ions ions

  • @jafwonta

    @jafwonta

    Жыл бұрын

    @@Caller8194 many textbooks refer to hydrogen ions as H+ ions. I don't get why it would be any different here

  • @Caller8194

    @Caller8194

    Жыл бұрын

    @@jafwonta H+ ions is wrong. Ask anyone with more than A level knowledge and they’ll agree

  • @miaxx3929
    @miaxx39292 жыл бұрын

    Hi, thanks for the video, I’m slightly confused on which voltage gated channels are open at the different stages of an action potential In an exam I wrote that the sodium ion channels are closed at resting potential, open at depolarisation and closed at repolarisation which was correct However when I wrote that potassium ion channels are open at resting, open at depolarisation and open at repolarisation it was marked incorrectly The mark scheme stated that the potassium ion channels are closed at resting, closed at depolarisation and open at repolarisation If you could give me any help with this I’d really appreciate it as I am slightly confused by this 😊

  • @lionqueen19

    @lionqueen19

    2 жыл бұрын

    I think it’s because some potassium ion channels are voltage gated and some aren’t, so some stay open all the time and the ones which are voltage gated require a particular environment to open for example the voltage gated channels open at +40 mV allowing potassium ions back into the cell which is why repolarisation occurs. The question was probably asking about voltage gated potassium ion channels so when you said they were open at resting potential, while the potassium ions that are not voltage gated are open because as the concentration of potassium ions increases inside the cell they want to diffuse out (so you were technically right there) but the voltage gated one’s remain closed? I’m sorry if that was confusing😭

  • @ozairmuddasir8578
    @ozairmuddasir85782 жыл бұрын

    maam u beauty

  • @MissEstruchBiology

    @MissEstruchBiology

    2 жыл бұрын

    I hope the video helped!

  • @ozairmuddasir8578

    @ozairmuddasir8578

    2 жыл бұрын

    @@MissEstruchBiology it did ma'am really very kind of u❤️

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