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008 The All-or-None Action Potential

Ever wondered why people refer to the action potential as “all-or-none”?

Well, I guess you’ll just have to watch the video above to understand. In this video, I use the kitchen sink, a paper towel and marbles to bring the concept home.

If you have any questions/comments, feel free to leave it in the comments field below.

- Leslie Samuel

Transcript of Today’s Video

Hey, this is Leslie Samuel again and I’m kind of excited today. I just posted a poll on my blog, and it was for you guys to help me to decide what the subtitle or slogan for Interactive Biology will be, and the one that you guys decided on was “Making biology fun.” So this is the first time I get to use this introduction. Are you ready for it?

Hello and welcome to Interactive Biology TV, where we’re making biology fun! I like the ring of that. I wasn’t going for that title before, but when you guys suggested it, when you guys voted on it, it really started getting me excited.

Anyhow, in today’s episode, we’re going to be talking about the all-or-none nature of the action potential. We’ve been talking about the nervous system, and depending on which book you read, it might say “all-or-none” or “all-or-nothing.” Either way, we’re talking about the same thing. Now, there are two terms that I want you to know for this episode. The first one is the axon hillock, and the second would be the threshold, okay? We’re in my kitchen today, and I’m going to be using a high-tech device to illustrate these concepts. So, let’s look at what we have here today.

Alright, so this is my high-tech device for today. I’m not going to be doing any dishes even though we’re by the sink, but hopefully, this will get you guys to understand the concept of the all-or-none nature of the action potential. So the two terms I said were the axon hillock and the threshold. Axon hillock is the place where the axon starts. We looked at the neuron and the parts of the neuron, and right where it goes from the soma to the axon, we have the axon hillock. That’s the first place we see voltage-gated ion channels. In a previous episode, I spoke about the proteins in the membrane, and you can go back to that and see what these voltage-gated ion channels do.

But anyhow, this is where action potentials can start. However, in order for them to start, the stimulation needs to be enough to bring it to the threshold. So this, we’re going to imagine that this is my axon hillock, and in order for an action potential to happen, this needs to break, and when this breaks, voltage-gated channels open and ions rush in, and we have that electrical signal.

So, these are my ions, the little blue marbles, and I’m going to put the first one on here and nothing happens, that’s not enough to cause an action potential. I’ll put the second one and nothing happens. This is a pretty strong piece of paper towel. It’s Brawny, and I think that’s the one where you see a really strong man on the plastic wrap, so that should say something about the strength, I think.

Anyhow, I’m going to continue putting, still no action potential. It has not reached threshold just yet, so I’m just going to continue putting these ions. I’m trying to bring it to threshold, but it’s not there as yet. And we’re going to put some more. Evidently, Brawny is pretty strong. No insult against Bounty or any of those other paper towels. But here we go, I’m going to continue putting more stimulation, more stimulation, nothing happens. It’s pretty strong, so let’s dump some more on there. At a certain point, it’s going to reach a point where…

Oh! There we go . . . it breaks and those ions get through. That point was the threshold. Now, up until that point, nothing happened. But once we reached that point, we reached the threshold, it’s enough stimulus to cause the action potential to happen. That is why we call it all-or-none.

So there you have it, it’s all-or-none. It’s either going to happen or it’s not going to happen. If there’s enough stimulation to reach the threshold, as you saw with this elaborate set-up, if there’s enough stimulation, it will cause an action potential. If there isn’t enough, it will not cause an action potential. That’s why we call it all-or-nothing, all-or-none. I hope you enjoyed this episode. If you have any questions or comments, leave them in the comments field below. I’d be happy to answer your questions. Who knows, I might even make a video to answer your specific question. That’s it for this video, and I’ll see you in the next one.

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Leslie Samuel is the creator of Interactive Biology. His mission is to use this site to Make Biology fun for people all over the world.

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Leave An AWESOME Comment

150 Responses to “008 The All-or-None Action Potential”

  1. allison adams January 27, 2011 at 10:25 am #

    Thanks for the great demonstration!! I understand this alot better now!

    • Leslie January 27, 2011 at 10:40 am #

      You are very much welcome Allison. Glad you are finding value in the videos!

  2. Rafaela Marques February 27, 2011 at 9:57 am #

    Your videos are just great!!! I’m a medicine student and they are helping
    me a lot at my physiology classes. Thank you very much (:

  3. InteractiveBiology March 8, 2011 at 7:33 am #

    @megaloveistheanswer You are very much welcome. Many more to come :)

  4. naqqiya March 10, 2011 at 1:51 pm #

    is all or none potential same as difference between action and graded potential?
    Thanks and loved you video….u rock…!!!!

    • Leslie March 10, 2011 at 2:59 pm #

      Hi Naqqiya,

      Glad you loved the video. All or none simply refers to the fact that the action potential either happens fully or doesn’t happen at all. The graded potential is not an action potential.

      That has to do with the fact that we can get different levels of membrane potential change depending on the stimulus. If those graded potential changes add up to reach the threshold, that will cause an action potential.

      All the best!

      • naqqiya March 11, 2011 at 2:04 am #

        thanks a tonne i now get my concept clear about graded potential. :)

        • Leslie March 12, 2011 at 6:41 pm #

          You are very much welcome Naqqiya :)

  5. InteractiveBiology March 27, 2011 at 4:08 pm #

    @megaloveistheanswer WOOOHOOOOO. That is SUPER AWESOME! Congratulations on passing your Biology exam. I’m so glad that the videos have helped you, and I will continue working like crazy to deliver more value.

  6. Farzana April 8, 2011 at 9:39 pm #

    Thank You SOOOOO much for making these videos. You are really helping me understand difficult concepts!! your the best!!

    • Leslie April 9, 2011 at 11:26 pm #

      Hi Farzana,

      Glad to know that it’s helping you understand difficult concepts. All the best!

  7. justanotheranatomystudent April 14, 2011 at 8:21 am #

    man, i have my anatomy test tomorrow, and I would not have been able to understand anything about how action potential works if it hadn’t been for your videos.

    thank you so much!

    • Leslie April 14, 2011 at 8:25 am #

      That’s awesome to hear. I’m so glad the videos were able to help. Stay tuned for more :)

  8. Simon Ben April 22, 2011 at 5:22 am #

    I see your video site. I would not abjectly understand about how action potential works. Have any help for me.

    • Lrsamuel April 22, 2011 at 9:55 am #

      Check out the videos page and you will see all of the content I have related to the Action Potential in the Nervous System section.

  9. jillmatte July 27, 2011 at 11:43 pm #

    Wow, I totally get it now! I am about to watch all of the videos that you have pertaining to what I am studying! You are a wonderful teacher!! Thank you!

  10. InteractiveBiology July 28, 2011 at 8:18 am #

    @jillmatte Thanks for the comment. Enjoy the rest of the videos, and subscribe, because there are many more coming ;)

  11. viju345 August 21, 2011 at 1:47 am #

    Thanx a lottttt…… Great 1……. Looking for other vdos

  12. viju345 August 21, 2011 at 1:47 am #

    Thanx a lottttt……
    Great 1…….
    Looking for other vdos

  13. InteractiveBiology August 21, 2011 at 7:48 am #

    @viju345 You’re welcome. Glad you are finding value in them.

    Stay tuned for many more!

  14. DevX August 27, 2011 at 9:15 am #

    When you said Hi Tech device I thought it’s going to be an iPhone again ;)
    Anyway your videos are great keep it going keep them coming ;)

  15. cyberxdev August 27, 2011 at 9:15 am #

    When you said Hi Tech device I thought it’s going to be an iPhone again ;)
    Anyway your videos are great keep it going keep them coming ;)

  16. InteractiveBiology August 27, 2011 at 10:15 pm #

    @cyberxdev Glad you are enjoying them. Stay tuned for many more :)

  17. InteractiveBiology August 27, 2011 at 10:15 pm #

    @cyberxdev Glad you are enjoying them. Stay tuned for many more :)

  18. T August 30, 2011 at 12:50 am #

    wow, you are sexy…

  19. tarajeano84 August 30, 2011 at 12:50 am #

    wow, you are sexy…

  20. InteractiveBiology August 30, 2011 at 9:50 am #

    @tarajeano84 LOL, umm . . . thanks? :)

  21. InteractiveBiology August 30, 2011 at 9:50 am #

    @tarajeano84 LOL, umm . . . thanks? :)

  22. criztofr September 7, 2011 at 2:27 pm #

    JUST GREAT!!!! educating and motivating!! And a pleasure to learn from such
    a happy teacher:) THANK YOU!!

  23. criztofr September 7, 2011 at 2:27 pm #

    JUST GREAT!!!!
    educating and motivating!!

    And a pleasure to learn from such a happy teacher:)

    THANK YOU!!

  24. InteractiveBiology September 7, 2011 at 6:49 pm #

    @criztofr :D Glad to know you are finding value in the videos ;)

    Many more coming!

  25. zackboomer September 18, 2011 at 6:00 pm #

    hey leslie are these videos detailed enough for a 3rd year university human physiology course? or something less advanced? thanks

  26. InteractiveBiology September 19, 2011 at 9:37 am #

    @zackboomer They are detailed enough when taken together. However, they aren’t the final source of info. Follow the guidelines your professor gives for his/her class and use these to supplement!

  27. vestraya September 20, 2011 at 8:05 pm #

    what happens before the threshhold level? like why do the blue marbles keep coming in?

  28. InteractiveBiology September 20, 2011 at 8:11 pm #

    @vestraya All questions are answered in the Interactive Biology community
    forums from now on. Go to the website in the description and then visit the
    community.

  29. vestraya September 21, 2011 at 6:15 pm #

    @InteractiveBiology where do i go when im on the website to ask questions?

  30. Sone Nine September 21, 2011 at 6:29 pm #

    @InteractiveBiology how come we have to go there now?

  31. vestraya September 21, 2011 at 6:29 pm #

    @InteractiveBiology how come we have to go there now?

  32. vestraya September 21, 2011 at 6:29 pm #

    how come we have to go there now?

  33. InteractiveBiology September 21, 2011 at 8:26 pm #

    @vestraya It’s easier on me.

  34. InteractiveBiology September 21, 2011 at 8:26 pm #

    It’s easier on me.

  35. drtitonew October 15, 2011 at 5:56 pm #

    believe me :- i love u from my heart

  36. InteractiveBiology October 15, 2011 at 8:34 pm #

    @drtitonew aww thanks :)

  37. InteractiveBiology October 15, 2011 at 8:34 pm #

    aww thanks :)

  38. hmelton1247 November 9, 2011 at 6:15 pm #

    the paper towel is a great metaphor for the threshold. that really makes
    sense now.

  39. hmelton1247 November 9, 2011 at 6:15 pm #

    the paper towel is a great metaphor for the threshold. that really makes sense now.

  40. hmelton1247 November 9, 2011 at 6:15 pm #

    the paper towel is a great metaphor for the threshold. that really makes sense now.

  41. InteractiveBiology November 10, 2011 at 1:07 pm #

    @hmelton1247 :) Thank you! Good to know you liked it. Do come back for more!

  42. InteractiveBiology November 10, 2011 at 1:07 pm #

    :) Thank you! Good to know you liked it. Do come back for more!

  43. dania gue ron November 26, 2011 at 5:17 pm #

    You DO make biology fun!!! Thank you thank you thank you :)

  44. daniagr23 November 26, 2011 at 5:17 pm #

    You DO make biology fun!!! Thank you thank you thank you :)

  45. InteractiveBiology November 27, 2011 at 10:12 pm #

    @daniagr23 You’re welcome! You’re welcome! You’re welcome! :) Please stay tuned. We have more Biology videos coming very soon to the site…

  46. InteractiveBiology November 27, 2011 at 10:12 pm #

    You’re welcome! You’re welcome! You’re welcome! :) Please stay tuned. We have more Biology videos coming very soon to the site…

  47. MzTeeKia905 November 30, 2011 at 1:27 am #

    Thank you!! I jumped when the paper towel broke.. LOL..

  48. MzTeeKia905 November 30, 2011 at 1:27 am #

    Thank you!! I jumped when the paper towel broke.. LOL..

  49. InteractiveBiology December 1, 2011 at 5:00 am #

    @MzTeeKia905 LOL! You’re welcome. :) Stay tuned for new Biology videos
    coming soon!

  50. InteractiveBiology December 1, 2011 at 5:00 am #

    @MzTeeKia905 LOL! You’re welcome. :) Stay tuned for new Biology videos coming soon!

  51. InteractiveBiology December 1, 2011 at 5:00 am #

    @MzTeeKia905 LOL! You’re welcome. :) Stay tuned for new Biology videos coming soon!

  52. InteractiveBiology December 1, 2011 at 5:00 am #

    LOL! You’re welcome. :) Stay tuned for new Biology videos coming soon!

  53. InteractiveBiology December 1, 2011 at 5:00 am #

    LOL! You’re welcome. :) Stay tuned for new Biology videos coming soon!

  54. EmpressLee75 January 7, 2012 at 6:20 pm #

    WOWWWW. Your examples are so clear, simple and direct. I enjoy listening to such an enthusiastic teacher, unlike my Uni lecturers. I was concerned about a test I have this coming Monday. I’ve been watching you for the last two days and I’m now looking forward to the test. Many, many THANKS to YOU. Blessings in ABUNDANCE :)

  55. Barberjg February 1, 2012 at 5:45 pm #

    Awesome videos thank you so much!

  56. Barberjg February 1, 2012 at 10:45 pm #

    Awesome videos thank you so much!

  57. ske8975 February 7, 2012 at 7:32 pm #

    You’re great!!! Keep making these videos and pass on these great ideas along to other teachers. They need to be like you.

  58. ske8975 February 8, 2012 at 12:32 am #

    You’re great!!! Keep making these videos and pass on these great ideas along to other teachers. They need to be like you.

  59. jdillla93 February 19, 2012 at 9:09 am #

    your videos are amazing. Im doing psychology & were currently learning about the CNS and the brain. I hated this and put it off for a whole week or two, im 19 and thats not good. I just want to say your practical videos & explaination is great. You really do make it fun ..well for me. im reffering everyone i know doing bio too you !

  60. jdillla93 February 19, 2012 at 2:09 pm #

    your videos are amazing. Im doing psychology & were currently learning about the CNS and the brain. I hated this and put it off for a whole week or two, im 19 and thats not good. I just want to say your practical videos & explaination is great. You really do make it fun ..well for me. im reffering everyone i know doing bio too you !

  61. mwicks06 February 27, 2012 at 6:02 am #

    These videos are just so simple, yet they help so much! Thank you!

  62. yadira4957 March 2, 2012 at 11:09 am #

    It helped so much thank you!

  63. yadira4957 March 2, 2012 at 4:09 pm #

    It helped so much thank you!

  64. toloveanatomy March 5, 2012 at 8:46 pm #

    Wow! You are FANTASTIC! Your explanation is FANTASTIC! I wish you were my teacher!!!!! I am in love with you and your lectures!!!!!

  65. toloveanatomy March 6, 2012 at 1:46 am #

    Wow! You are FANTASTIC! Your explanation is FANTASTIC! I wish you were my teacher!!!!! I am in love with you and your lectures!!!!!

  66. zephyr45450 March 17, 2012 at 7:54 am #

    jazakAllah…for this video …keep sharin..such viseos take care..

  67. zephyr45450 March 17, 2012 at 11:54 am #

    jazakAllah…for this video …keep sharin..such viseos take care..

  68. lynexeye March 17, 2012 at 3:03 pm #

    Just like everybody, I would love to say too that Thank you so much. You are so helpful and easy to understand. Love your Videos… Please Upload more Videos about Different other Parts/Organs of the Body… Keep looking for your incoming videos..Loves and Regards from Pakistan <3

  69. AimeeleForain March 18, 2012 at 1:15 pm #

    Thank you so much! You are so nice and everything is easy to understand! I am from
    Germany ;) keep up the good work!

  70. AimeeleForain March 18, 2012 at 5:15 pm #

    Thank you so much! You are so nice and everything is easy to understand! I am from
    Germany ;) keep up the good work!

  71. campaspe810 March 20, 2012 at 9:28 am #

    What is it with americans and wood kitchens…

  72. campaspe810 March 20, 2012 at 9:28 am #

    What is it with americans and wood kitchens…

  73. campaspe810 March 20, 2012 at 1:28 pm #

    What is it with americans and wood kitchens…

  74. divoniarosemond March 21, 2012 at 12:48 pm #

    love what you are doing but i have adhd so please stick to the subject and get to the point a little faster……. please i need you to pass my nremt exam !

  75. divoniarosemond March 21, 2012 at 4:48 pm #

    love what you are doing but i have adhd so please stick to the subject and get to the point a little faster……. please i need you to pass my nremt exam !

  76. Joyce March 21, 2012 at 11:49 pm #

    Thank you so much! You have an awesome explanation! Now I understand the action potential works in our body.
    You’re explanation really helps.

    • Leslie Samuel March 23, 2012 at 4:01 pm #

      Glad to hear the video helped you.

      All the best!

  77. JanisRNdream March 24, 2012 at 12:11 am #

    Thank you, Love your stuff Only negative is adding in what kind of ions they are , sodium ions rush in.. I already knew but some may not know those facts, I subscribed and have a test on Monday 4 chapters so I will be watching you all weekend :)

  78. JanisRNdream March 24, 2012 at 4:11 am #

    Thank you, Love your stuff Only negative is adding in what kind of ions they are , sodium ions rush in.. I already knew but some may not know those facts, I subscribed and have a test on Monday 4 chapters so I will be watching you all weekend :)

  79. mvillasanac March 30, 2012 at 2:47 am #

    Wow, man. You and your explanations are great. Congratulations.

  80. mvillasanac March 30, 2012 at 6:47 am #

    Wow, man. You and your explanations are great. Congratulations.

  81. gina rimbey April 4, 2012 at 12:48 pm #

    your teaching is exciting and fun! thank you

  82. Anonymous April 4, 2012 at 4:48 pm #

    your teaching is exciting and fun! thank you

  83. gina rimbey April 4, 2012 at 4:48 pm #

    your teaching is exciting and fun! thank you

  84. berryhouseful April 11, 2012 at 9:35 pm #

    Could you please be my tutor? I would definitely get a 4.0! You are amazing..definitely gonna watch all your vids! Thank you! :)

  85. berryhouseful April 12, 2012 at 1:35 am #

    Could you please be my tutor? I would definitely get a 4.0! You are amazing..definitely gonna watch all your vids! Thank you! :)

  86. silverlining723 April 16, 2012 at 2:11 am #

    Is the amount of stimulation before threshold is reached the graded potential?

  87. silverlining723 April 16, 2012 at 6:11 am #

    Is the amount of stimulation before threshold is reached the graded potential?

  88. JaredAugerot April 17, 2012 at 11:17 pm #

    you should do Google AdSense for brawny or whatever towel you used.

  89. JaredAugerot April 18, 2012 at 3:17 am #

    you should do Google AdSense for brawny or whatever towel you used.

  90. MHCOCC April 22, 2012 at 12:46 am #

    This was a great way to explain this concept-thanks for making this a very visual explanation-now I won’t forget the ‘all or none’ aspect!

  91. MHCOCC April 22, 2012 at 4:46 am #

    This was a great way to explain this concept-thanks for making this a very visual explanation-now I won’t forget the ‘all or none’ aspect!

  92. ai18able April 27, 2012 at 3:33 pm #

    Peace be upon you Mr. InteractiveBiology :)
    can you make a video on mechanism of muscle contraction and relaxation?really hope you can help me.
    thank you! :)

  93. ai18able April 27, 2012 at 7:33 pm #

    Peace be upon you Mr. InteractiveBiology :)
    can you make a video on mechanism of muscle contraction and relaxation?really hope you can help me.
    thank you! :)

  94. InteractiveBiology April 27, 2012 at 8:03 pm #

    Hi! You’ll find Episodes 041 to 043 at Interactive-Biology about muscle contraction. Hope they’ll help. Have fun!

  95. InteractiveBiology April 28, 2012 at 12:03 am #

    Hi! You’ll find Episodes 041 to 043 at Interactive-Biology about muscle contraction. Hope they’ll help. Have fun!

  96. wendic1 April 29, 2012 at 8:02 am #

    Thank you so much for your explanations. They are really helping me understand.

  97. wendic1 April 29, 2012 at 8:02 am #

    Thank you so much for your explanations. They are really helping me understand.

  98. Lisa Ledwidge May 3, 2012 at 1:43 pm #

    Could you add in a note to the video on what you mean when you say “stimulus”? Thanks. Your videos are helpful! I like that they are short. I’m planning to recommend them to my A&P students.

  99. Lisa Ledwidge May 3, 2012 at 1:43 pm #

    Could you add in a note to the video on what you mean when you say “stimulus”? Thanks. Your videos are helpful! I like that they are short. I’m planning to recommend them to my A&P students.

  100. SaraSiraj May 7, 2012 at 9:16 pm #

    Thank you very much, I read my text book many times & couldn’t clearly understand the concept until I watched your video. Keep the amazing work & God bless you!

  101. SaraSiraj May 7, 2012 at 9:16 pm #

    Thank you very much, I read my text book many times & couldn’t clearly understand the concept until I watched your video. Keep the amazing work & God bless you!

  102. stikkle55 May 23, 2012 at 12:16 pm #

    is action potential the same as the electrical pulse?

  103. stikkle55 May 23, 2012 at 12:16 pm #

    is action potential the same as the electrical pulse?

  104. ethan forrest June 1, 2012 at 2:30 am #

    is there a video on how nerve signals travel?

  105. ethan forrest June 1, 2012 at 2:30 am #

    is there a video on how nerve signals travel?

  106. reality237 July 6, 2012 at 11:56 pm #

    lol paper towel jokes are hilarious real helpful video though!!!!

  107. reality237 July 6, 2012 at 11:56 pm #

    lol paper towel jokes are hilarious real helpful video though!!!!

  108. blueBruSea September 12, 2012 at 8:49 pm #

    Your video is amazing. What’s amazing is that a concept I had to reread multiple times was answered just by watching your video once. Great job with all the videos so far. They’re fun, interactive, easy to grasp, and concise. Thank you :D

  109. tommysmommy2 September 14, 2012 at 8:44 am #

    LOVE your videos–show them to my psych class often. Thank you.

  110. churchboy19 September 16, 2012 at 6:37 am #

    your amazing ;) and more

  111. yasminhabibty September 20, 2012 at 5:03 pm #

    Amazing, and I really mean it. Thanks a lot. I was moved by the creativity of this episode. Just like you hoped that we enjoyed this show. I thoroughly enjoyed it.

  112. missrej123 September 28, 2012 at 4:49 am #

    Im learning a lot from your vids Sir. Im a nursing student and I stopped for a year, and Im refreshing my mind from the things that arent clear from me before. now I fully understand these things now:))) I will prepare myself from passing board exam;)

  113. RainbowxxMartini October 9, 2012 at 4:05 am #

    Thank you so much for picking up the slack of my bio teacher. He is so lazy and condescending. I’m so happy that I stumbled upon your videos! You are definitely helping my mark :)

  114. Barbi32105 November 27, 2012 at 3:44 am #

    you are a very good teacher.. i like the method you use to teach.. i am going to take microbiology next semester i hope i can find more videos that can help me get a good grade =)

  115. Hyperiontje January 8, 2013 at 8:46 pm #

    Hats off to you for answering every question out there. All your videos are very well structured and easy to understand difficult concepts. Big up!

  116. googke101 January 29, 2013 at 10:49 pm #

    Is that a Southern Adventist University water bottle by the sink?
    Mind = Blown
    I go to Union College, another Adventist college in Nebraska. Thanks for your videos!

  117. tsizemore1982 February 14, 2013 at 1:17 am #

    Again. Another awesome video. If only my Adv. A+P class was as interesting as your videos. =)

  118. Rachel Hickey February 26, 2013 at 8:42 pm #

    can you explain how the ion channels open/close and why..with the Na and K..?

  119. Anastasja Mendelev March 6, 2013 at 12:40 pm #

    Beautiful demonstration.

  120. Carvo Loco March 7, 2013 at 7:24 am #

    What do you mean? Biology is fun already!

  121. AYYYkay47 March 22, 2013 at 5:46 pm #

    you are great!! love the videos!

  122. hristo hristov March 30, 2013 at 9:13 pm #

    Hey guys. Nice film.

    My older brother had been obese. He went from 283 lbs of fat into 200 lbs of purely natural muscle mass. I used to be shocked. I just subscribed personally as I must greatly improve my overall physique. He used the Muscle Building Bible (Search on Google)…

  123. bellabella bella April 6, 2013 at 6:06 pm #

    Thanks

  124. jkmissa April 17, 2013 at 8:21 pm #

    this video is awesome. I laughed so hard when you talked about the big strong brawny man. You really do make biology fun!

  125. philippalexander1994 April 21, 2013 at 8:43 am #

    Hey, i am from germany, but never the less i understand your videos pretty well, thank you! :-)

  126. TheMysthicalWhore May 30, 2013 at 4:49 pm #

    Hi I need an answer for question – what is the difference between AP in musle fibre (or nerve fibre) and whole musle (or nerve). I think, in the first case, it is about this law (all or nothing), and in the second case it is about summation of APs of each fiber?? But Im not sure…thank you! Silvia.

  127. MCFitnessPT June 17, 2013 at 12:06 pm #

    Who’d thumb this down? Seriously, best description ever, and he’s making it fun, good job Leslie!

  128. Leeann Gooding July 5, 2013 at 5:29 pm #

    amazing explanation

  129. kingq katl July 9, 2013 at 3:53 am #

    MAN THIS GUYS TEETH R SO FUKING WHITE

  130. deboracruzlove July 9, 2013 at 11:18 pm #

    you are great! Thanks.

  131. Ali Stratton July 10, 2013 at 2:41 pm #

    Hahaha! I love your paper towel jokes! Thanks so much for posting fun, interesting, and easy to understand videos! They are absolutely wonderful!

    God bless!!!

  132. Smita Patil August 22, 2013 at 1:31 pm #

    things made soo simple! :)

  133. lilyellaboneshawty August 28, 2013 at 11:55 pm #

    this helped me a lot. i like how u use different settings and props in ur videos to teach the lesson!

  134. Ghosty Coman September 9, 2013 at 5:26 pm #

    Your home is gorgeous, by the by. Mine looks nowhere near so neat, even the corners that you probably didn’t expect to get videotaped, haha.

  135. عبدالعزيز بنان October 11, 2013 at 9:49 am #

    thank you . you are great

  136. nathanb605 October 14, 2013 at 2:55 pm #

    love this guy !

  137. Nikhil Thomas October 27, 2013 at 2:04 pm #

    Yo yo… Awesome clip clip.

    My close friend was once a flabby. He went from 284lbs of pure fat into 217lbs of genuine muscle. I couldn’t believe it! I just joined personally coz I’m working to get stronger muscles. He made use of the Muscle Building Bible (Look in Google)…

  138. dee November 12, 2013 at 3:32 am #

    thank you

  139. Nadinakin November 13, 2013 at 11:30 am #

    I got a question regarding the voltage threshold.
    Does a stimulus bring ions? Otherwise, where do the sodium ions that cause
    a rise in the voltage (to reach the certain threshold) come from? ?

  140. Nadinakin November 13, 2013 at 11:30 am #

    I got a question regarding the voltage threshold.
    Does a stimulus bring ions? Otherwise, where do the sodium ions that cause
    a rise in the voltage (to reach the certain threshold) come from? ?

    • Quamy Burrdy January 23, 2014 at 2:28 pm #

      just sweet! nice illustration man i wasnt getting it but now i do

  141. collins June 20, 2014 at 5:55 am #

    Thanks Leslie. You are a blessing. Keep doing to the good work