Action Potential in the Neuron

This animation demonstrates the behavior of a typical neuron at its resting membrane potential, and when it reaches an action potential and fires, transmitting an electrochemical signal along the axon. It shows how the various components work in concert: Dendrites, cell body, axon, sodium and potassium ions, voltage-gated ion channels, the sodium-potassium pump, and myelin sheaths. It also shows the stages of an action potential: Polarization, depolarization, and hyperpolarization.

The animation was co-developed by Harvard Extension School's Office of Digital Teaching and Learning, and instructors for the courses in neurobiology and human anatomy.

[bluehourcore]

you literally just explained what takes up more than 10 pages of my textbook in a video that's shorter than 15 minutes. tysm!

[rachelthellammaa]

I wish everyone well for the upcoming test!
You got this!

*Update: I'm now in college and I found myself coming back to this video since I have an exam tomorrow. Still extremely helpful!

[GGG]

Every sentence is literally a ¨punchline¨. I wish schools around the world had the ability to convey the material that way, instead of confusing their students. well done harvard.

[simranc]

It took me an hour to get through the whole video because I kept pausing it to get almost two pages of notes out of it. Thank you so much!

[travisk]

Can I say that I went to Harvard after watching this video

[_Understand_it]

This is by far the best explanation of action potentials I've ever come across. Thanks!

[mikeish]

If anyone is wondering, there are things called leaky K+ gates that always allow a little bit of K+ ion movement across the membrane. This is how the resting potential is restored after hyperpolarisation (when it goes to negative). Because it's so negative inside the cell (below the resting potential of -70mV) K+ ions will move into the cell because of the electrical gradient, sodium ions can't their gates are shut. This movement of K+ ions into the cell makes it more positive and restores the resting potential. The sodium potassium ion pumps do help a little to maintain the electrical gradient, but mostly they keep the chemical gradient (Na+ in high concentration outside, K+ high conc. inside) with the leaky K+ (how many / how leaky they are) determining the electrical gradient and therefore the resting potential.

[DannietheSWAMPY]

As a first year neuroscience student, my lectures on the introduction to this topic was covered over 3 hours and was very confusing to understand. This managed to keep the level of detail needed whilst keeping it simple and also under 15 mins... Thank you so much, this really helped.

[Alex-dpbk]

My professor couldn't make this make sense for the entire two semesters I had him. This one video explained it all to me in just 13:11. Thank you.

[teresagaines]

I’m on page 4 of notes! I can’t believe how much this video is helping me understand what I believe is going to be a large topic on my midterm for an SFSU psychology course titled “Perception.” I’ve been struggling to conceptualize brain structures and brain activity that is now included in my courses. I’ve never seen any of it before and have had to slowly teach myself through videos like this when, even after re-reading the dense textbook, I still struggle to keep it all clear. As a very passionate psych undergrad who has never had to take chemistry or any class past intermediate biology, this video made me feel like I really missed out on appreciating science classes more because now that it was explained in a way I can understand, it blew my freakin mind. God I love learning.

[maheen]

this 13 min video covered this content way better than my professor's 40 minute video

[leilacx]

great video, i understand why Harvard students are so smart, if your explanations are this good online, I cannot imagine how great the lecture are in person.

[nancywei]

In my class they don't explain this stuff easily and non-complicated. This is like a dream, where all the complicated parts are filtered out and all the important things are here. Thank you Harvard this should be in all lectures and lessons about neurons

[theorionnebula]

as a homeschooled kid making my own cutriculum, thank you for this resource. i learned about ion channels the other day and was like “wtf those things do” then was looking into the specific cell functions of neurons and thwy came up bigtime. everything is connected

[veroniquelevesque]

I can't thank you enough for this video. I am a big visual learner and this should be presented in all physiology classes. Wow!

[aakashsaha]

I was so baffled by the Neuroscience introductory class. This video made me understand the process so easily. More videos on topics like this are appreciated. Thank you...

[mernus]

Make the video x1.25, then it becomes normal

[katjorbar]

It all finally makes sense! This video is brilliant in its simplicity and cuts out all the fluff that made it complicated!

[spacemaster]

I am 14 and obsessed with a level psychology: This video was very useful, particularly for clarification and being clear and concise!
For anybody confused:
Basically the dendrites are decorated with synapses, which don't quite touch the next axel, but have literally less than 1 millionth of an inch between them. The dendrites decide whether to pass the stimulation on, and if yes, then the process begins. The stimulation is passed through the cell membrane (soma), through the axel (which is often covered in a layer of protective fat called the myelin sheath) where the action potential then reaches the axel terminal, and the action potential "jumps" across the synaptic gap and into there receptor sites (like a key fitting into a lock).

[davidthomaschwclmt]

I wish my A and P teacher would just show this video. its so helpful