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What is an Action Potential?
That’s the question I’m answering in todays Interactive Biology Episode. Watch the video above to find out 
This is the first in my new video format and I really hope you enjoy it.
Once you have finished watching the video, go ahead and leave your comments below.
If you have any questions, that would be the place to ask them.
- Leslie Samuel
Transcript Of Today’s Video
Welcome to another episode of Interactive Biology TV. My name is Leslie Samuel. In this video, I’m going to be answering one basic question: What is an action potential? You’re probably going to notice that it’s a little different than the 6 episodes that I’ve done before. And the 2 main differences that you’re going to notice are:
- I no longer call it BioVid. The reason for that is “Biovid” doesn’t really tell what this is all about. I’ve changed it to Interactive Biology TV, because it’s going to be interactive, it’s going to be about biology, and it’s going to be a video. So from now on, you’re going to hear me say “Interactive Biology TV” as opposed to “BioVid.”
- You’re going to notice that I’m on camera this time, and that’s a little different because in the past, I’ve done slides and animations and so on. The reason I’m making this change is basically because I wanted to do something that I can produce much quickly. In the last year, I only made 6 episodes, and I want to be doing episodes on a regular basis and this is just easier for me to produce and I can put together a relatively professional-quality video in a short period of time.
I hope you enjoy this new format. Please let me know in the comments below, and if you have questions or comments about it, you can just do that. It’s going to be relatively laid-back and I’m just going to be talking to you about these different concepts.
So, let’s get into the content for today. Today, I’m answering the question “What is an action potential?” If you’ve looked at any of the previous episodes, you’ve seen that I’ve given an introduction to the nervous system and to neurons. That introduction to neurons basically comes right before this in terms of understanding the concepts, the different parts of the neuron.
Now, the main part of the neuron that we’re going to be talking about today is the axon. I have a very amazing device here that I’m going to be using to illustrate that. The axon is the part that sends the signal. A signal starts in the soma, there’s processing that happens in the soma, and we’re going to talk about that later on. It sends a signal via the axon, to the ends of the axon, the axon terminals, and then that signal can basically go to the next neuron.
How I’m going to illustrate this is really simple. If someone touches your hand, you feel it. And the reason you feel it is because there are signals that start at that point, and the signals go to your spinal cord, and then up to your brain. These are electrical signals that happen relatively quickly, so that your brain can interpret that stimulation, and your brain tells you “Okay, someone is touching you.”
That is an action potential. You can call it an action potential, you can also call it a nerve impulse, but it’s basically that electrical signal that goes from that stimulation point all the way to the brain. And these signals are going on throughout the body, doing a bunch of different things, and we’re going to talk about that.
So, here we have my handy-dandy iPhone 4. I’m going to turn it on. And I have my earbuds, I’m going to put these on. I’m assuming you guys know how this works, but the iPhone 4 is an amazing device. It has built-in an iPod, and I’m going to assume you know what an iPod is. You know what, I’m going to tell you what an iPod is, just for some strange reason you don’t know what an that is. It’s an MP3 player that allows you to play music and audio books and a whole bunch of other stuff.
Anyhow, I’m going to stimulate this iPhone, and it’s going to send an electrical signal via this cable to the earbuds, and we’re going to assume as if it’s going to my brain. And it is going to my brain. So, here we have a cable sending signals, and then there can be a response. The brain can interpret that stimulation. Okay, so I’m going to press Play, and this is me stimulating. And as soon as I press Play, I can hear music. I can dance to the music, I can do a whole bunch of stuff. Let me stop that for now.
But basically, here we have that wire, and these are the axons of the neurons sending signals to the brain, to different parts of the body. It’s basically how the nervous system communicates with the different cells and organs and the glands. So, really simple, the action potential is that signal that goes through the axons along the nerves and basically takes a signal from one place to another place, whether that’s from the brain to my hand that pulls away, whether it’s from the stimulation point all the way to my brain.
I hope that makes sense for you. That’s basically what an action potential is. If you have any questions, comments, leave it below in the comments field. I’d be happy to follow up and answer your questions, or even make a video about it. That’s it for this episode, and I’ll see you on the next one.
About The Author Leslie Samuel
Leslie Samuel is the creator of Interactive Biology. He created this site to help Make Biology Fun and has the goal of making this the biggest and best biology resource on the net.
9. February 2012 at 1:23 pm
No you know that the Na channels are stimulated by the voltage changes..The depolarization state will cause a difference in voltage, this will stimulate any nearby Na channels to open…K channels are slower than Na ones in closing, Na channels on the first end of Action pot. will wait for K channels to be closed, Na chan. won’t open even if there was a stimulus as long as K chan. are opened…This will cause the movement of Action pot. in one direction in the axon..
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9. February 2012 at 1:30 pm
@Caribbeanpearl09 simpler, at the first end of action potential Na channels have been opened once earlier…It won’t be opened again until the K channels closed…at the second end Na channels haven’t been opened earlier, think of them as virgins, so any change in voltage will open them, then Na chan. will be closed in the new area of the axon, K will open, Na will wait for them to close in order to be able to open again, virgins of the newer area will open…and so on and so on…
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9. February 2012 at 1:30 pm
simpler, at the first end of action potential Na channels have been opened once earlier…It won’t be opened again until the K channels closed…at the second end Na channels haven’t been opened earlier, think of them as virgins, so any change in voltage will open them, then Na chan. will be closed in the new area of the axon, K will open, Na will wait for them to close in order to be able to open again, virgins of the newer area will open…and so on and so on…
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12. February 2012 at 8:49 am
what is resting potential?
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16. February 2012 at 7:54 pm
Awesome! I am a TA for a College Anatomy course and I refer students to your videos for clarification and review.
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16. February 2012 at 7:54 pm
Awesome! I am a TA for a College Anatomy course and I refer students to your videos for clarification and review.
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21. February 2012 at 3:07 am
Can You do a video on how the electrical impulse traveled through out the axons and what causes them to move?
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27. February 2012 at 10:49 am
Wayne brady? is that you? just kidding
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10. March 2012 at 10:08 pm
your teeth.. wow white.
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15. March 2012 at 5:18 am
great vid, thanks man
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15. March 2012 at 2:16 pm
Hi! We use your episodes in our cardiology class in Belgium! They are really helpfull, although in the beginning we thought our teacher was a bit lazy..
Greetings!
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19. March 2012 at 6:23 pm
Thank you so much for posting all this videos. God Richly Bless You!!!!!
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20. March 2012 at 9:48 am
i don’t think, that black ppl should think about things like that… come on… seriously… u should sell drugs or shit like that dog!
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23. March 2012 at 1:43 pm
if you have a problem with black people, then hop off the vid.
ignorant people like you NEED to DIE!
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27. March 2012 at 1:01 pm
Thank you so much. you really make biology fun.
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30. March 2012 at 9:58 am
such kidding dog
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30. March 2012 at 9:58 am
such kidding dog
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30. March 2012 at 9:59 am
i’m even black
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30. March 2012 at 9:59 am
i’m even black
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30. March 2012 at 9:59 am
in mind
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30. March 2012 at 9:59 am
and white on skin
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30. March 2012 at 9:59 am
and white on skin
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1. April 2012 at 5:26 pm
This is too simplistic even for teenagers. Who is your target audience?
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3. April 2012 at 11:30 pm
Please tell me apple are paying you for this!
Anyways, awesome vid, keep it up.
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3. April 2012 at 11:30 pm
Please tell me apple are paying you for this!
Anyways, awesome vid, keep it up.
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4. April 2012 at 4:56 am
our teacher use this video’s for the lesson’s in the university. it makes the lesson’s more amusing
and it makes studying a little bit easier 
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5. April 2012 at 12:26 pm
Tanx for this wondeful add…pls i would some lectures on G proteins
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8. April 2012 at 9:34 pm
merci mile fois de vos amis de Canada!
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14. April 2012 at 2:56 am
SO GOOD! I’ve found a video that makes learning this stuff easier. Thank you
Top shelf!
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14. April 2012 at 2:42 pm
Hey,
Awesome videos can you please do one on blood,red and white cells and plateletes
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15. April 2012 at 4:45 am
You rock, Leslie. Keep helping make our world smarter.
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18. April 2012 at 6:37 pm
thanks for video but the explaination of action potential is more than what he said.
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18. April 2012 at 6:37 pm
thanks for video but the explaination of action potential is more than what he said.
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26. April 2012 at 4:08 am
Glad I found your video because I couldn’t grasp the reading material and when I saw your video I then felt kind of like wow I can understand that LOL..anyways I look forward getting educated by your videos.
God Bless
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1. May 2012 at 6:19 pm
Dude, this is so great! Thanks a lot for putting so much time into all this. It’s so helpful!
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1. May 2012 at 6:19 pm
Dude, this is so great! Thanks a lot for putting so much time into all this. It’s so helpful!
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2. May 2012 at 9:10 pm
awsome put siri to ur iphone 4!!!!!!
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2. May 2012 at 9:10 pm
awsome put siri to ur iphone 4!!!!!!
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5. May 2012 at 2:43 pm
you forgot the actual action potential with a sodium potassium pump
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6. May 2012 at 9:50 am
i feel like im getting one on one tutoring! you are amazing!!
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6. May 2012 at 9:50 am
i feel like im getting one on one tutoring! you are amazing!!
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6. May 2012 at 8:06 pm
You are an amazing teacher
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6. May 2012 at 8:06 pm
You are an amazing teacher
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7. May 2012 at 1:34 am
This guy is cool. Is it racist that I always think black people are cool?
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9. May 2012 at 9:38 am
sir is mutation beneficial?
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9. May 2012 at 9:39 am
is mutation beneficial?
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10. May 2012 at 6:45 pm
1:28 to start.
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12. May 2012 at 4:31 pm
i think i love you x
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12. May 2012 at 10:59 pm
studying for the AP bio exam and this is really helping me clarify a lot of stuff that weren’t as clear as before! thanks for these videos!
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