The Nervous System, Part 2 - Action! Potential!: Crash Course Anatomy & Physiology #9

[@daniellelutchman485]

I really can't get over how selfless this is. Thank you so much

[@katie98711]

they get the money from youtube so it is not THAT selfless but it is amazing they dont want people to pay them, incredible, i love this

[@sakurablossom1123]

I'm sure the money they get helps fund the quality content we get from the animations to other resources. And fund them eating, which means they live so that all of this content can exist period, lol.

[@italiana7308]

Danielle Lutchman ?????

[@kunalchaudhari9806]

👍

[@myriahkeays3846]

Vianney Eudes hey those gaming channels help me laugh in the middle of a mental breakdown thank you very much

[@ali-v3387]

crazy this is free and more people understand then in school

[@ali-v3387]

damn right bow to your king

[@ali-v3387]

grammar is for bitches

[@dimethaltryptamine1]

Sir Ali-V, you are a sexist uneducated know it all FOOL! Learn to express yourself in a less egocentric way. Leave out your sexist remarks & learn correct spelling & the correct meaning of words & your remarks may be taken more seriously. Using 'then' not 'than' in the context of your remark is a spelling mistake not a grammatical error! Stooping to Sarcasm & sexism is a sign of ignorance in a person in a verbal disagreement.

[@dimethaltryptamine1]

+Layla B He doesn't know the difference between a spelling error & a grammatic one :) Add the sexism & it's also "Good luck being a man" lolz

[@lordmasterization]

Don't feed the troll.

[@aphroditejoe17]

When you're in college and you don't understand the instructor but this makes more sense than the person you're paying to teach you...

[@olamergo3172]

Same! I'm currently at the university and I was using crash course to prepare for IB finals in high school but this content is very useful even today!

[@Joel-oe7ud]

Exactly😂😂

[@shannon-daygrant8754]

BIGGEST BUBBLE = academia. Once accreditation becomes more decentralized - it will be radically restructured; and good!

[@ziiiziii1989]

Im graduating this semester, and in my graduation's speech im gonna thank you instead of my professors!!!!!

[@samanthaleigh454]

+zomorrod rouhi amen

[@t.solares6323]

When I do in more than 6 years I will do that too lol😂😂😂 not even kidding I am a nerd 🤓 for knowledge

[@carinajessurun1125]

Same here!

[@nuclearwarfareaw]

Say "Nah nah na boo boo on you!" to your professor.

[@shonacole2124]

agreed

[@rdorta81]

I can't believe how in 11 minutes I learn more than a 5 hour class of neurology.

[@soniamartell9220]

Same for me and my anatomy class!

[@周小倩-o2g]

roman dorta I feel the same

[@bryceplant2087]

He's awesome and takes longer just edit out spaces

[@reshram4118]

Sooooooo true

[@eenkjet]

So far the epistemology is completely wrong and based on Hogkin Huxley which is dead.

[@jorgeromeu]

On average 10 minutes of crash course is equal to 5 hours of regular class. You are a true hero Hank.

[@raneemhamada7318]

That moment he says "You probably know enough about biology by now to know that nature hates gradients," and you look down in shame because you have no idea what he's talking about.

[@rains5]

Lol

[@RK-ep8qy]

Raneem Hamada osmosis, diffusion, electrochemical gradients in photosynthesis and respiration and just basic equilibrium. You do you know, it just didn’t click till later. Dw

[@maddieandchrisboyle3058]

Gradients are just differences basically, and nature loves equilibrium. So he just means nature always tries to find balance AKA no gradient

[@hamstersdailylife4938]

it might help if you look up the word "homeostasis", but I can tell you're just trying to add a fun commentXD

[@dreallday07]

JusyClouds I thought this was a fat joke, I’m now proud of my eq

[@shamskhalid9138]

Those 11 minutes were literally more useful than a two hours class. Can't thank you enough.

[@medslarge]

Approximately 85 times better than my school notes/text. Especially because you explain things like the myelin sheath and sodium potassium pump in context with the rest of the things that are happening in the cell - THANK YOU CRASHCOURSE

[@wem3121]

07:43 When I finished the video I was kinda in a hurry and I hit my toe across the door. I was like "The current is currently flowing in the axons now bear with it repolarization is coming and you won't feel the pain anymore" haha Thanks a bunch for the the effort :D That helps a lot.

[@Hope4freedom76]

I'm so glad this channel exists. I have no background in science whatsoever so you'd understand the initial shock and confusion and despair i was in when i studied these topics. Text books are so confusing and hard to read! Thank god for Crash Course #Atleasticangetapassnow

[@nuclearwarfareaw]

God doesn't exist.

[@HarisAli-sw5xr]

You don't exist.

[@thegoldenradio8858]

+Andy Wang Nothing exists, only perception and theory

[@FirstRisingSouI]

I always wondered what happened in my nerves when elephants crawled across my knees.

[@aliciabarrenger4618]

Are you selling "Nature Hates Gradients" T-shirts? I would totally buy one.

[@zopilote_4000]

+Alicia Barrenger please

[@alessandraristerportinarim5214]

i need em'

[@wasimmunshi429]

@@alessandraristerportinarim5214 You don't need them. *You want them*. All you need is air, water and nutrition.

[@yashbahl4334]

@@wasimmunshi429 you're so right

[@gim5816]

@@wasimmunshi429 and Jesus

[@thefinnishsocialist4816]

You've literally made the university courses that I've taken and made them more intuitive, brief, and appealing. I can't believe that people end up thousands in debt when they literally could've just watched CrashCourse on youtube to get the same information. You're doing a great work here and you have my respect.

[@jaymsleedan]

I like need to borrow your brain for this exam I'm about to take. Do you mind?

[@dorianken1487]

same

[@saidalkakar6923]

I bet you will end up writing "Biology hates gradients" lol

[@manu-iman]

How did the exam go?

[@ananda3363]

I'm dead but still alive college is a thing

[@lindam3839]

I’ve watched this at least 15 times in the last 2 weeks for my exam. It’s just so much easier than to read a book that never gets to the point, or to listen to a professor who glazes over it. Thank you!!

[@zannacart8533]

Thank you I needed this for my psychology test! It was difficult to understand this in my text book.

[@Walsh2571]

+Tiffany Amber Heh that's funny, i'm watching this for my physics course.

[@j.j.r98]

+Tiffany Amber me too

[@MeleDrummer]

+Walsh2571 I'm watching it for neurophysiology :-D

[@THECH1NA]

+MDrummer Anatomy here :P

[@sadeema1942]

+HubyAnn Physiology herrre C:

[@mochasani9791]

Still helping students in 2019!!💗💗💗

[@sudharsanvj8531]

QUESTION: After hyper-polarization, how does the Na-K Pump restore balance (I mean increase the positive charge inside the cell), if it throws out 3 positive ions out of the cell and brings inside only 2 ? Shouldn't it make the insides of the neuron more negative ? ANSWER: When the inside of the cell becomes more negative than -70mV, then the sodium channel which is closed starts leaking and more Na+ ions start entering the cell due to the strong repulsion between the positive charges on the outside (Note: Even after the sodium channels open and close there should still be a lot of Na+ ions outside the cell than inside). So the leakage in the Na+ channel makes the inside of the cell more positive while Na-K pump makes it more negative. Both of them work together and maintain that sweet spot of -70mV. Hope this helps. Have a good one.

[@ansiis4754]

Sudharsan V J THANK YOU

[@cassmills4509]

You literally just taught me more than my A&P professor. Thank you so much king

[@travisbickle3835]

bro how did this guy managed to fit in a week worth of my physiology classes to a 11 minute video 💀 and I understood it better 💀 you are a wizard my friend

[@AilenProof]

This is the video that got me into biology, I'm a computer science student and I find it so interesting how the brain interprets code just like computers.

[@thegaspatthegateway]

Obo DOS I know right! When you look at that and DNA, the parallels are eerie ^o^ I want to get into neuroscience, and use it to develop artificial intelligence

[@rains5]

It should be the other way around.

[@nate_whitaker]

Teya Logos yes’m

[@rebeccahobson6220]

Hank! My Hank! You have got me through some very hard exams...very well I may add. Thank you. I would be lost without Crash course. You guys are selfless and wonderful. Now my daughter is really interested in science, she is using you guys to look up questions that her teacher cannot answer. I cannot thank you enough. You are awesome. Keep up the fantastic work.

[@CrysBean-q9i]

This is so awesomee. It literally is so easy to understand. Im just 15 years old, still in highschool and I understood with a bit of pausing and reflecting of what I understood and I thought it was like a lesson or topics that is a high school topic and then I realized its literally a college course OMG👀❤️❤️🍀 this is just so awesome

[@lnmock]

As an FNP student, I just have to say thank for you really breaking down this complex subject. I haven't taken an A&P class in over 10 years, so this is such a good refresher. My professors suggest these videos for their students to review because it is explained more clearly than a dull textbook.

[@MsLozeh]

I am taking a biology class for my nursing degree. Once I watched this everything clicked for me because i couldnt get this concept by reading it in my text book and such. thanks Hank!

[@Ab.Stat.]

Vlogbrothers and Co. have begun something truly wonderful with this channel. Crashcourse is one giant leap toward the democratised future of knowledge which the Internet has promised to deliver since its inception. I struggle to express the admiration and gratitude I hold for all those who contribute toward the project, including the subbable base.

[@ryanpius5873]

what

[@Jeudaos]

surprisingly enough, this 'app' function he refers too, is exactly how touch displays work on smart devices. I remember reading about it. Touch screen displays use Action and Potential sodium and potassium charges to manipulate the on screen icons.

[@katieannestead]

You sir are a legend, i get assignments.... i youtube you. For this i salute you.

[@kazaakas]

These video's are of superb quality, everything from editing, to explanation and even that nice studio. Downright amazing.

[@anitaalyabiev]

I feel so much well-informed and confident to do my tests when watching these videos. Learned more in these short few minutes than any lesson or textbook. Thank you Crash Course!!!

[@heydebee]

ilysm

[@maryb4493]

This is so selfless! Hank (the man In the video.) decides to spend time educating others on this channel when he could be making million as a chief professor in biology! Thanks Hank!

[@sanaamin5651]

May God bless you for keeping this free!! I am doing my graduation through correspondence(homeschooling) and this has helped so much! ! Honestly I dont need classes at all because I have you guys to explain me things better than professors! Keep up the good work! You got the blessing of millions of students!😇

[@Zile.e]

Oh no! A cliffhanger! Or should I say...synapse-hanger? Yeah? No? Cause...the charge is hanging on the edge of the synapse, ready to jump the cleft? No? Okay.

[@5nefarious]

*weak applause?*

[@DrymouthCWW]

Crickets.... Then roaring laughter and applause.

[@JackKenton]

Points for trying friend.

[@Zile.e]

:'D Thanks.

[@Zile.e]

ibtihaj chowdhury It's the thought that counts...or moves across the charge gradient! *badum-tssss* (take this power away from me!)

[@stephentapp4814]

I'm in 6th grade and homeschooled. I love watching you biological videos as they are amazing and easy to understand! Thanks for your posts!

[@aurelia2180]

This 11 minute video has helped me more than my past 10 weeks of biology class. Seriously, you guys do such an amazing job. I'm definitely coming back to your channel to help me with my biology and chemistry

[@emily-mn2oj]

I'm so sad I only discovered this channel the night before my exam!

[@sophielane6839]

Same!

[@raven-1490]

how was your exam?

[@tanyatumbeva7279]

When you get the "a-ha" moment with Hank.

[@KristenWalston]

I love this. I'm trying to cram anatomy and physiology in a week. Final exam is Friday. I have gotten so much more out of this video series than the 14 unit book and 27 page study guide.

[@julianadurandelgado6426]

Love this guy... "this is action potential, in action" lol

[@cleverokposin]

Can I just point out how beautifully and excitingly you explained these concepts... Thank you

[@sheepwshotguns]

like buttons aren't enough, i need to click a love button.

[@rebeccar5934]

but don't we all.

[@phenomenalphysics3548]

sheepwshotguns same

[@JorgeVargas-sp8vn]

I'm forever grateful for you. My future kids will definitely use crash course as a way to wrap up what they've read in text. I'm a proud science nerd.

[@tryhardnoob1140]

Being a computer engineering major, i find this absolutely facinating to actually be able to understand how this works. Excellent explanation.

[@snapshotshawna1548]

I'm learning this for my brain and behavior class. It's for my psychology major. Very hard class.

[@Kawaiimuscles]

I love Craah Course I was struggle with Physiological Psychology but no more. Thanks for helping me graduate

[@MKP131]

My teacher is a physicist. He wrote the biology portion of our textbook in the hope that the biologists on the team would rewrite it. They did not. So, in order to understand this concept (which he admitted is too hard and boring for even him) I turn to you, Hank. Thank you. You save my bacon.

[@dessertthingy]

I've spent hours/days reading about this in my anatomy book, and this made more sense. Thank you.

[@srobinson6592]

I freaking love this show, It's just so pure and educational and fun to watch. I hope y'all will keep up the good work!!

[@raptoryzb]

The whole "Nature Hates Gradients" bit made my day, 10/10.

[@daniellabenjamin7149]

It's a perfect speed. If you u press pause, I can take it all in and reinforce it. Thank you, for speaking quickly. Nice work.

[@augustusself8119]

Love the little animations on the side, and this makes learning so enjoyable!

[@lemon5896]

Thank you - I was so close to giving up on studying this - you made it 100000 times easier for me to study !

[@FrontendTopics]

I can't believe how well everything was explained. Those animations are awesome. The way the content is organized it's great. When I have to read about different topics for university it's difficult to understand how everything connects together, but here the script it's so clear! At the end everything makes sense.

[@aphilemdluli]

Thank you so much. I have learnt so much. Thank you for your selfless work.

[@eggplnt]

I am very excited about crash course kids! I have been wanting to share these with my 5th graders, but they are too advanced. I can't wait for these!

[@thelonelydirector]

We're seriously excited about it. :D

[@thegaspatthegateway]

kids totally deserve this, it'll be like their Bill Nye

[@asad817]

eggplnt hi random teacher

[@emmacharlotte6538]

If it wasn't for these videos I'd definitely be failing Monday's biological psychology exam. THANK YOU! You make this understandable 😱

[@t.solares6323]

Yes it's easy enough for an 11-year-old person to understand or me I love AP

[@katiebunt4715]

I'm with you! I'm studying for Bio Psych course too and these videos are a life saver!

[@thankunext1625]

girl im taking biopsychology right now and my first exam was literally today, this is a life saver 😩🙏

[@headrockbeats]

Awesome, I've seen some children around, so tomorrow I'm going to take my windowless white van and go tell them all about Crash Course Kids!

[@gregmiller9710]

lmao

[@missc2742]

HEY! Our moustachioed and oddly touchy band director has been missing a van just like that!! You didn't steal it, did you?!

[@headrockbeats]

Madame Catfish Oh, you mean Fred? Errr... I mean... no, of course not. **whistles nonchalantly**

[@dhartmahmed50]

Headrock I'm calling the police!The nonchalance gave it away kiddo

[@rains5]

Weird imagery

[@lawrencecalablaster568]

Thank you, Hank, for helping me remember how the action potential works for my neuropsychology test tomorrow :)

[@sophelisabeth8819]

Thank you so much! been struggling with this so much in my A Level Biology but you've explained it so well and made it so much easier to understand. Thank you

[@lovelovelovekayan]

You are making me feel more comfortable when I see my lecture notes. I have a better understanding of action potential!

[@camillarose3072]

Thank you CrashCourse for making this make sense, entertaining, and memorable! I'm going to school to become a teacher and am very excited for crash Crash Course Kids ! Thanks so much for all the hard work you peoples do to make quality videos. p.s. I do believe in God who design our complex body, world, and universe. Science is discovery and understanding how things work. The chances for a single cell creature to form out of nothing is astronomical. It takes a lot more faith to believe in the big bang than a God who designed the universe.

[@simonazigova3253]

This is amazing, you guys helped me pass my anatomy exam a and you´re helping me with physiology. Big massive THANK YOU !

[@solankisneha3562]

excellent work has been done by your team... each and every detailing and explanation is just efficient... comparatively bestest videos and easy to understand... everything simplified

[@cheryl2915]

I love Crash Course!! Thank you for another tool I can use to aid in the understanding our amazing and complex body systems.

[@triceratopsinitriceratop7228]

This is truly a life saver🙏

[@katedo7555]

I am stress from biology class but can’t deny that biology is amazing, there are many things you need to learn and also be grateful to the scientists. I think one of the method of doing well in biology class is learn to love biology.

[@hannahnelly1193]

Have a BME exam tomorrow and this really helped me understand. Thanks!

[@XTheSpartanX7]

You guys are amazing. I sometimes watch your videos multiple times. First time i just watch it at .75 speed, second time same speed, but i take notes and last time i just watch it at normal speed.

[@jellen6505]

Anyone else thinks he'll be an awesome rapper😂😂

[@h86k42]

mmmmmeee

[@renadgalal14]

omg i just wrote that

[@eashwarsm6697]

Watch the video in 2x and there u have the answer

[@sabrinalopez1420]

yap

[@turkishandmore798]

but kudos to you as well for being able to catch up with every single detail he said and clearly relate ! it’s either our fantastic brain capacity or his perfect way of spilling things out ! 😂

[@FaithNMB]

I have a physiology test next week and this has honestly helped me so much!!! Thank you!!!

[@charitymitchell7174]

I know every one does this but THANK YOU FOR HELPING ME PASS A+P.

[@Soulfreequensea]

Your channel is SO HELPFUL and descriptive, keeps my mind engaged. Thank you

[@divagurl985]

This was so interesting! Yes I feel nerdy but it feels good lol. I've always had trouble remembering/understanding this concept. Thanks!

[@fatimashaikh9712]

The best explained video I have ever watched.. 👍👍

[@godlikestevie]

Teacher took 2 years to try and explain his; got it all in just 10 minutes. Thanks, very helpful.

[@rolienfuls9535]

Thank you SO MUCH for all the effort you put in and don't even have to pay, you save my grades and bank account 😅❤

[@AngelTerri]

Watching this I really hope my neurons are that happy

[@jayjay1517]

Hats off to you! Highly informative, entertainingly presented, well produced etc etc. thankyou.

[@lienia83]

This guy is Awesome! He explain things so easy no matter the science

[@ohlookadandelion]

i really don't need all the extra information that crash course gives while explaining stuffs, but that's the reason i watch u guys- I LOVE HOW U EXPLAIN EVERYTHING IN DETAIL and it helps so much clearing each concept!

[@EdixaSanchez1]

"would like to breathe sometime soon..." lol!

[@nunyabuziness5733]

Damn man we use you in class because of me you are loved more than you know keep making amazing videos forever❤

[@DKlarations]

Super excited for NerdyAndQuirky !!!

[@crashcourse]

We are too! She's awesome! -Nicole

[@joellowe647]

CrashCourse just wanted to say thanks to you guys and Hank this has to be the most interesting crash course I've seen so far

[@henrypeterson211]

Joel Lowe I second that.

[@bullterry14]

Henry P-S I third that

[@septicoblivion]

bullterry14 i fourth that XD

[@TheSchoellerFamily]

Thank you!! This was so helpful!

[@melanieazevedo3328]

I love this guy! Always keeps me intrigued, easy to process, and even get a little chuckle from time to time! :)

[@Emma-vb7of]

This is my second time watching this have a real interest in it maybe someday I might decide to go to college but right now you guys are my teachers and I'm so so grateful.. So thank you again!! Videos are always really entertaining to watch and this host is a legeng I love his apathetic attitude😂 Nature always finds a way to balance things out, that's what's happening atm with this virus , scary shtufff. Anyways hope everyone's keeping safe.. it's 5AM in the morning idk what I am doing 😂😂

[@priceaka13]

Understanding free content on youtube and Im paying big bucks at school for it smh

[@turkishandmore798]

this is indescribable !! so seamless and clear a true biology tutor is the one who let us in the true identity of biology which is intrinsically LIFE SCIENCE , this was so life and i could easily relate it to my actual neuron activity !!!!

[@thegaspatthegateway]

Could never afford college, so thank you for this amazing resource on my faaaav subject! :D you are truly awesome

[@miltianaholdip1635]

Finals coming up next week and I refuse to read those PowerPoints 😂 videos it is

[@MisterMajister]

at 9:35 it says that the sheeting of the oligodendrocytes doesn't leave space for Nodes of Ranvier. According to Vander's Human Physiology both PNS and CNS has those nodes. However, really educational and is helping me a lot with my physiology course!

[@ErthanaCx]

+MisterMajister Kolb&Whishaw (An introduction to brain & behaviour) state the same thing. This was my first time ever hearing that CNS axons don't have nodes o.O

[@anthonycerda481]

I believe what it's trying to say is that the nodes in the PNS are covered in Schwann cells which have basal lamina that surrounds the cell and continues over the node, while the oligodendrocyte nodes in the CNS are bare, meaning they don't have these "regular nodes of ranvier gaps"

[@Erica-kp6is]

I have been watching Hank since Biology 1610 and he helped me pass for my second time since the first time I had no idea what my teacher was saying! He explains it so much better in less time! Now I am watching in Anatomy and getting amazing help from him once again! Thanks, Hank and everyone else in crash course! :)

[@Pbmarron]

I'm taking AP 1, and this 11 minute video makes more sense than a 2 & 1/2 hour lab lecture.

[@Youknowwho910]

Watched a bunch of other videos on yt about this topic but this is the only content that made sense. Thanku so much!

[@meghagupta6402]

I love how I'm getting an entire crash course of my exam 2 hours before I take it and learning better than I ever did in my lectures

[@micahclark7919]

I wish you were my professor. The way you explain these concepts is so much clearer and direct than my professor who just reads off of a powerpoint. I would show up to class on time every day, sit in the front of the class, and actually be motivated to learn and participate rather than sleeping.

[@LironAbesdid]

Love Crash Course!!!!