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.
Neural mechanism: * The neuron is stimulated hard enough to send one signal each time at one uniform strength and speed. * The impulse is called an action potential * The brain translates the AP and understands them by their frequency * The body is electrically neutral but has in some areas a separation between the positives and negatives which creates a potential to generate electricity Measuring the AP: * The voltage is the measurement of potential energy generated by separated charges. It is called the membrane potential in neurons measured in mV * The current is the flow of +ve or -ve ions from one point to another. It is equal to the voltage divided by the resistance * The resistance is what is getting in the way of the current which is the cells’ membranes * The cell membranes separate the oppositely charged ions creating a potential to convert the electricity to something useful Resting neurons: They are more negatively charged on the inside of the cell relative to the positively charged extracellular surroundings. This difference is the resting membrane potential which is -70mV * The outside (surrounding) has a lot of +vely charged sodium ions * The inside (neuron cell) has some +vely charged potassium ions and a lot of -vely charged proteins which makes the overall charge negative * The neuron having a negative membrane potential is said to be polarized Sodium-potassium pumps: To distribute these ions, there are sodium-potassium pumps: * The membrane of the neuron is mounted by many sodium-potassium pumps. * For every two potassium ions that are pumped into the cell, three sodium ions are pumped out. This makes the outside more +vely charged * This difference is an electrochemical gradient Ion channels: To even out the charges again, there are ion channels: * Most are voltage-gated channels that open and close in response to changes in membrane potential (e.g. sodium channels which open at around -55mV) * Ligand-gated channels which open only when a specific neurotransmitter latches onto its receptor (e.g. serotonin or a hormone) * Mechanically-gated channels which open in response to physically stretching the membrane When the channel opens, the ions diffuse across the membrane down their electrochemical gradient to even out the concentrations while repelling other positive ions. This movement of ions is the key to all electrical events in the neurons Graded potential vs action potential: * Graded potential: * The stimulus is very weak * Only a few ion channels open and a bit of sodium enters the cell * A little change in the membrane potential occurs in a localized part of the cell * Action potential: * The stimulus is strong enough * Voltage-gated channels are triggered * A big change in the membrane potential occurs * A long distance signal is sent all along the axon Depolarization: * It starts with the neuron at resting state with closed ion channels and the inner voltage is at -70mV * An environmental stimulus occurs * The sodium channels are triggered to open which increases the charge inside the cell * The stimulus and change have to cross a threshold which is about -55mV (all-or-nothing phenomenon) * At the threshold, the voltage-gated sodium channels open and the sodium rushes into the cell making it highly depolarized that it becomes +vely charged (up to 40mV) * This is the action potential which is a temporary reversal of membrane potential or a brief depolarization caused by changes in currents * The AP sends off a biological chain reaction which sends the electrical signal down the axon. Each neuron has lots of voltage-gated sodium channels, so when a few in one area open, the local current is strong enough to change the voltage around them which triggers neighboring channels then the voltage around those and this continues down the axon * Then repolarization starts Repolarization and hyperpolarization: * The voltage-gated potassium channels open and the potassium ions flow out to rebalance the charges * At first, the flow of potassium ions is too much and the membrane briefly goes through hyperpolarization * The voltage drops to -75mV * The gates close and the sodium-potassium pumps work to bring things back to resting level Refractory period: It is when an axon has open ion channels and can’t respond to other stimuli. It prevents signals from traveling in both directions down the axon at once * Absolute refractory period: it is the first phase of this period lasting from depolarization to repolarization. It makes sure that each AP is its own unique all-or-nothing event * Relative refractory period: the second phase lasting from repolarization through hyperpolarization and back to resting potential Afterwards, it can receive another stimulus when it is back to resting potential AP characteristics: The AP always has the same strength but differs in: * Frequency: * A weak stimulus results in a low frequency of AP * A strong stimulus results in a high frequency of AP * Speed/conduction velocity: * Some pathways are faster (e.g. those for reflexes) * Some pathways are slower (e.g. those in the glands, guts, and blood vessels) * Larger axon diameter conducts signals faster because they offer less resistance, so they allow AP to happen faster * Myelin increases the speed of conduction since instead of triggering one channel at a time in a chain rxn, a current can leap from one gap in the myelin to the next. The gaps are called Nodes of Ranvier and this type of propagation is called saltatory conduction
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.
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.
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
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.
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
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
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!!
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.
Pssst... we made flashcards to help you review the content in this episode! Find them on the free Crash Course App! Download it here for Apple Devices: apple.co/3d4eyZo Download it here for Android Devices: bit.ly/2SrDulJ
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.
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.
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!
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.
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!
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.
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
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.
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!!!
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!😇
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.
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
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.
This is totally saving my butt. I have a PSY 312 (Brain and Behavior) test in the morning, and for the life of me, I could not grasp neurotransmission. This just made it so much easier to grasp than any book or powerpoint I have looked at.
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
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.
Hi crash course! I am studying neuroscience in Oxford while I study abroad here, and I love using these videos to help me alongside my studies! Crash course is my go-to resource, even in the Bodleian libraries!
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.
I'm in a hearing science class and we need to know this, but the professor explains things very blandly and without much enthusiasm so the info kept going in one ear and out the other. This is SO HELPFUL. Especially the animations.
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.
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.
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.
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!
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.
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! :)
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 !!!!
In my college-prep Anatomy course, In the lesson I only wrote down one paragraph of notes, in an hour's time... Here I wrote down a whole page of notes in 11 minutes. Thank You!
As a college student learning about Biology (which isn't the most interesting thing in the world to me, honestly) I find Crash Course to be invaluable in breaking things down into layman's terms that I can understand - thank you folks so much!
I agree to all the comments stating this is video is very easily understood. Although I am a native Japanese living in Japan, I also feel this 10min video is better than all of my school education and workbooks.Thank you crash course!
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.
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
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
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
Thank you again for another fab course. I am a registered nurse and frequently come back to these sessions for a refresher. My only bit of advice - the speed of delivery is fast! Keeping up with the detail can be challenging, thank goodness for rewind 😁
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!
+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
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"
Boy I'd like to breathe sometime soon! Edit: I am so grateful for this tutorial you have no idea how helpful this was. Essays are hard, essays on subjects you barely understand are even harder but this lifted some of the burden off of me.
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 😂😂
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 ! 😂
I really can't get over how selfless this is. Thank you so much
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
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.
Danielle Lutchman ?????
👍
Vianney Eudes hey those gaming channels help me laugh in the middle of a mental breakdown thank you very much
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...
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!
Exactly😂😂
BIGGEST BUBBLE = academia.
Once accreditation becomes more decentralized - it will be radically restructured; and good!
I can't believe how in 11 minutes I learn more than a 5 hour class of neurology.
Same for me and my anatomy class!
roman dorta I feel the same
He's awesome and takes longer just edit out spaces
Sooooooo true
So far the epistemology is completely wrong and based on Hogkin Huxley which is dead.
Neural mechanism:
* The neuron is stimulated hard enough to send one signal each time at one uniform strength and speed.
* The impulse is called an action potential
* The brain translates the AP and understands them by their frequency
* The body is electrically neutral but has in some areas a separation between the positives and negatives which creates a potential to generate electricity
Measuring the AP:
* The voltage is the measurement of potential energy generated by separated charges. It is called the membrane potential in neurons measured in mV
* The current is the flow of +ve or -ve ions from one point to another. It is equal to the voltage divided by the resistance
* The resistance is what is getting in the way of the current which is the cells’ membranes
* The cell membranes separate the oppositely charged ions creating a potential to convert the electricity to something useful
Resting neurons:
They are more negatively charged on the inside of the cell relative to the positively charged extracellular surroundings. This difference is the resting membrane potential which is -70mV
* The outside (surrounding) has a lot of +vely charged sodium ions
* The inside (neuron cell) has some +vely charged potassium ions and a lot of -vely charged proteins which makes the overall charge negative
* The neuron having a negative membrane potential is said to be polarized
Sodium-potassium pumps:
To distribute these ions, there are sodium-potassium pumps:
* The membrane of the neuron is mounted by many sodium-potassium pumps.
* For every two potassium ions that are pumped into the cell, three sodium ions are pumped out. This makes the outside more +vely charged
* This difference is an electrochemical gradient
Ion channels:
To even out the charges again, there are ion channels:
* Most are voltage-gated channels that open and close in response to changes in membrane potential (e.g. sodium channels which open at around -55mV)
* Ligand-gated channels which open only when a specific neurotransmitter latches onto its receptor (e.g. serotonin or a hormone)
* Mechanically-gated channels which open in response to physically stretching the membrane
When the channel opens, the ions diffuse across the membrane down their electrochemical gradient to even out the concentrations while repelling other positive ions. This movement of ions is the key to all electrical events in the neurons
Graded potential vs action potential:
* Graded potential:
* The stimulus is very weak
* Only a few ion channels open and a bit of sodium enters the cell
* A little change in the membrane potential occurs in a localized part of the cell
* Action potential:
* The stimulus is strong enough
* Voltage-gated channels are triggered
* A big change in the membrane potential occurs
* A long distance signal is sent all along the axon
Depolarization:
* It starts with the neuron at resting state with closed ion channels and the inner voltage is at -70mV
* An environmental stimulus occurs
* The sodium channels are triggered to open which increases the charge inside the cell
* The stimulus and change have to cross a threshold which is about -55mV (all-or-nothing phenomenon)
* At the threshold, the voltage-gated sodium channels open and the sodium rushes into the cell making it highly depolarized that it becomes +vely charged (up to 40mV)
* This is the action potential which is a temporary reversal of membrane potential or a brief depolarization caused by changes in currents
* The AP sends off a biological chain reaction which sends the electrical signal down the axon. Each neuron has lots of voltage-gated sodium channels, so when a few in one area open, the local current is strong enough to change the voltage around them which triggers neighboring channels then the voltage around those and this continues down the axon
* Then repolarization starts
Repolarization and hyperpolarization:
* The voltage-gated potassium channels open and the potassium ions flow out to rebalance the charges
* At first, the flow of potassium ions is too much and the membrane briefly goes through hyperpolarization
* The voltage drops to -75mV
* The gates close and the sodium-potassium pumps work to bring things back to resting level
Refractory period:
It is when an axon has open ion channels and can’t respond to other stimuli. It prevents signals from traveling in both directions down the axon at once
* Absolute refractory period: it is the first phase of this period lasting from depolarization to repolarization. It makes sure that each AP is its own unique all-or-nothing event
* Relative refractory period: the second phase lasting from repolarization through hyperpolarization and back to resting potential
Afterwards, it can receive another stimulus when it is back to resting potential
AP characteristics:
The AP always has the same strength but differs in:
* Frequency:
* A weak stimulus results in a low frequency of AP
* A strong stimulus results in a high frequency of AP
* Speed/conduction velocity:
* Some pathways are faster (e.g. those for reflexes)
* Some pathways are slower (e.g. those in the glands, guts, and blood vessels)
* Larger axon diameter conducts signals faster because they offer less resistance, so they allow AP to happen faster
* Myelin increases the speed of conduction since instead of triggering one channel at a time in a chain rxn, a current can leap from one gap in the myelin to the next. The gaps are called Nodes of Ranvier and this type of propagation is called saltatory conduction
crazy this is free and more people understand then in school
damn right bow to your king
grammar is for bitches
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.
+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
Don't feed the troll.
Im graduating this semester, and in my graduation's speech im gonna thank you instead of my professors!!!!!
+zomorrod rouhi amen
When I do in more than 6 years I will do that too lol😂😂😂 not even kidding I am a nerd 🤓 for knowledge
Same here!
Say "Nah nah na boo boo on you!" to your professor.
agreed
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.
Lol
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
Gradients are just differences basically, and nature loves equilibrium. So he just means nature always tries to find balance AKA no gradient
it might help if you look up the word "homeostasis", but I can tell you're just trying to add a fun commentXD
JusyClouds I thought this was a fat joke, I’m now proud of my eq
On average 10 minutes of crash course is equal to 5 hours of regular class. You are a true hero Hank.
Those 11 minutes were literally more useful than a two hours class. Can't thank you enough.
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.
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
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
God doesn't exist.
You don't exist.
+Andy Wang
Nothing exists, only perception and theory
I always wondered what happened in my nerves when elephants crawled across my knees.
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!!
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.
Pssst... we made flashcards to help you review the content in this episode! Find them on the free Crash Course App!
Download it here for Apple Devices: apple.co/3d4eyZo
Download it here for Android Devices: bit.ly/2SrDulJ
awesome! thank you!
This is amazing, thank you for making them even after 5 years. You all are awesome!!
CrashCourse are you from heaven? ♥️🦄
Are you selling "Nature Hates Gradients" T-shirts? I would totally buy one.
+Alicia Barrenger please
i need em'
@@alessandraristerportinarim5214 You don't need them. *You want them*. All you need is air, water
and nutrition.
@@wasimmunshi429 you're so right
@@wasimmunshi429 and Jesus
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.
I like need to borrow your brain for this exam I'm about to take. Do you mind?
same
I bet you will end up writing "Biology hates gradients" lol
How did the exam go?
I'm dead but still alive college is a thing
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.
Thank you I needed this for my psychology test! It was difficult to understand this in my text book.
+Tiffany Amber Heh that's funny, i'm watching this for my physics course.
+Tiffany Amber me too
+Walsh2571 I'm watching it for neurophysiology :-D
+MDrummer Anatomy here :P
+HubyAnn Physiology herrre C:
You literally just taught me more than my A&P professor. Thank you so much king
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!
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.
Sudharsan V J
THANK YOU
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!
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.
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
It should be the other way around.
Teya Logos yes’m
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.
what
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!
Still helping students in 2019!!💗💗💗
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!!!
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!😇
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.
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
These video's are of superb quality, everything from editing, to explanation and even that nice studio.
Downright amazing.
Being a computer engineering major, i find this absolutely facinating to actually be able to understand how this works. Excellent explanation.
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.
You sir are a legend, i get assignments.... i youtube you. For this i salute you.
This is totally saving my butt. I have a PSY 312 (Brain and Behavior) test in the morning, and for the life of me, I could not grasp neurotransmission. This just made it so much easier to grasp than any book or powerpoint I have looked at.
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.
I'm so sad I only discovered this channel the night before my exam!
Same!
how was your exam?
Can I just point out how beautifully and excitingly you explained these concepts... Thank you
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
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.
Hi crash course! I am studying neuroscience in Oxford while I study abroad here, and I love using these videos to help me alongside my studies! Crash course is my go-to resource, even in the Bodleian libraries!
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.
ilysm
like buttons aren't enough, i need to click a love button.
but don't we all.
sheepwshotguns same
I'm in a hearing science class and we need to know this, but the professor explains things very blandly and without much enthusiasm so the info kept going in one ear and out the other. This is SO HELPFUL. Especially the animations.
I'm learning this for my brain and behavior class. It's for my psychology major. Very hard class.
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.
If it wasn't for these videos I'd definitely be failing Monday's biological psychology exam. THANK YOU! You make this understandable 😱
Yes it's easy enough for an 11-year-old person to understand or me I love AP
I'm with you! I'm studying for Bio Psych course too and these videos are a life saver!
girl im taking biopsychology right now and my first exam was literally today, this is a life saver 😩🙏
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.
Teacher took 2 years to try and explain his; got it all in just 10 minutes. Thanks, very helpful.
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.
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!!
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!
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.
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! :)
The whole "Nature Hates Gradients" bit made my day, 10/10.
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 !!!!
I love Craah Course I was struggle with Physiological Psychology but no more. Thanks for helping me graduate
I know every one does this but THANK YOU FOR HELPING ME PASS A+P.
Thank you - I was so close to giving up on studying this - you made it 100000 times easier for me to study !
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.
Have a BME exam tomorrow and this really helped me understand. Thanks!
In my college-prep Anatomy course, In the lesson I only wrote down one paragraph of notes, in an hour's time... Here I wrote down a whole page of notes in 11 minutes. Thank You!
I've spent hours/days reading about this in my anatomy book, and this made more sense. Thank you.
As a college student learning about Biology (which isn't the most interesting thing in the world to me, honestly) I find Crash Course to be invaluable in breaking things down into layman's terms that I can understand - thank you folks so much!
This is amazing, you guys helped me pass my anatomy exam a and you´re helping me with physiology. Big massive THANK YOU !
I agree to all the comments stating this is video is very easily understood.
Although I am a native Japanese living in Japan, I also feel this 10min video is better than all of my school education and workbooks.Thank you crash course!
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.
*weak applause?*
Crickets.... Then roaring laughter and applause.
Points for trying friend.
:'D Thanks.
ibtihaj chowdhury It's the thought that counts...or moves across the charge gradient! *badum-tssss* (take this power away from me!)
You are making me feel more comfortable when I see my lecture notes. I have a better understanding of action potential!
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
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
When you get the "a-ha" moment with Hank.
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
Understanding free content on youtube and Im paying big bucks at school for it smh
I have a physiology test next week and this has honestly helped me so much!!! Thank you!!!
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!
We're seriously excited about it. :D
kids totally deserve this, it'll be like their Bill Nye
eggplnt hi random teacher
I don't think anyone understands how much this has saved my life all throughout both my Anatomy & Physiology classes
Thank you, Hank, for helping me remember how the action potential works for my neuropsychology test tomorrow :)
Damn man we use you in class because of me you are loved more than you know keep making amazing videos forever❤
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
These videos are reinforcing what I learned so far in class for the Nervous system in my Nursing School.
This was so interesting! Yes I feel nerdy but it feels good lol. I've always had trouble remembering/understanding this concept. Thanks!
Thank you again for another fab course. I am a registered nurse and frequently come back to these sessions for a refresher. My only bit of advice - the speed of delivery is fast! Keeping up with the detail can be challenging, thank goodness for rewind 😁
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!
+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
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"
Boy I'd like to breathe sometime soon!
Edit: I am so grateful for this tutorial you have no idea how helpful this was.
Essays are hard, essays on subjects you barely understand are even harder but this lifted some of the burden off of me.
Could never afford college, so thank you for this amazing resource on my faaaav subject! :D you are truly awesome
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 😂😂
I love Crash Course!! Thank you for another tool I can use to aid in the understanding our amazing and complex body systems.
Seriously this is amazing. You all are making a difference in the grades of millions. :')
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!
lmao
HEY! Our moustachioed and oddly touchy band director has been missing a van just like that!! You didn't steal it, did you?!
Madame Catfish Oh, you mean Fred? Errr... I mean... no, of course not. **whistles nonchalantly**
Headrock I'm calling the police!The nonchalance gave it away kiddo
Weird imagery
Watched a bunch of other videos on yt about this topic but this is the only content that made sense. Thanku so much!
Anyone else thinks he'll be an awesome rapper😂😂
mmmmmeee
omg i just wrote that
Watch the video in 2x and there u have the answer
yap
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 ! 😂
I saw the video and title on my timeline but I can’t watch it.🥺 Sending you love, prayers and strength Hank and daily. You got this!!! 💪❤️🩹🙏
Watching this I really hope my neurons are that happy
Your channel is SO HELPFUL and descriptive, keeps my mind engaged. Thank you
This guy is Awesome! He explain things so easy no matter the science