Cardiovascular | Electrophysiology | Intrinsic Cardiac Conduction System

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Ninja Nerds,
In this lecture Professor Zach Murphy will be presenting on the Intrinsic Cardiac Conduction System. We hope you enjoy this lecture and be sure to support us below!
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Couldn’t agree more... so underrated

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Hey..! May i ask you one question?

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yeah we gotta make sure he has enough money to keep this free for the next generation.

[@feefeee]

I hope med school is going well.

[@linahasisen7608]

Remember TIC -> TAC 1. Troponin T binds tropomyosin 2. Troponin I binds Actin 3. Troponin C binds Calcium

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Thank You kind soul!

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Thanks

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❤️

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Brilliant!!!

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TicTac

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"DON'T YOU DARE LAUGH AT ME, IM SHORT" lol !!! i love your videos !!

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Oh that was cute!

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Perfect

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🤣🤣🤣🤣🤣

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[@goxusphere]

Attended more than 15 cardiovascular physiology lectures in medical school, but your 48 mins video taught me a lot more. You are amazing man.

[@sunvavachi]

Felt the same...was so well done.

[@faithcharfauros4892]

Ahmet X Ninja Nerd is very thorough and has the great ability to actually teach. He articulates very well.

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@@faithcharfauros4892 yes you are true

[@kismatrajpurohit4522]

I missed my physiology lecture but now I have no regret..

[@nadsar6165]

@@kismatrajpurohit4522 that was in your kismat btw😀

[@songyardbird2513]

Dude you may not be tall but you sure as hell ain't short. You tower over any professor I have ever had.

[@ASalfity]

Brief Table of Contents: 4:20 - SA Node 6:20 - Bachmann's Bundle 7:10 - Internodal Pathway 8:10 - AV Node 9:50 - Bundle of His 12:40 - Bundle Branches 13:10 - Purkinje fibers 15:40 - Nodal Cell 23:10 - Connexons 26:00 - Contractile Cell 35:20 - Sarcoplasmic Reticulum 37:20 - Troponin 39:50 - Functional Syncytium Nice videos, thanks. How do the potassium ions make their way back into the cells? Or is that in another video. You may want to add this (or your own improved) table of contents to the description. Maybe someone else can post a detailed table of contents as this is just a brief one.

[@robinsonokoye5245]

Bless you 🙏

[@muhammadmuaziqbal]

I assume it is through the Na-K ATPase, 3 Na+ go out in exchange of 2 K+ coming in with utilisation of ATP. In the nodal tissue, the funny channels create enough of [Na+] inside the cell. And in the muscle cell, Na-Ca channels of both sarcoplasmic reticulum and the cell membrane(sarcolemma) does the same, i.e., create enough conc. of Na in cytoplasm for Na-K ATPase to function. P.S.: I'm not sure about this but that's what I assumed as it seemed correct. Please correct me if I'm wrong

[@rezamdfardeen9727]

Hats off bro

[@sukhmansingh5723]

Good job

[@Persistance123]

Na-k antiport maybe

[@emilyreeves7854]

"BEAUTIFUL gap junctions!!" I love your enthusiasm:) The human body IS really cool, so it boggles my mind when professors drone on monotonously in lectures. I want to shake them and say GET EXCITED. Thanks for the awesome content. Can't wait to get my first "real" job after graduation and give your channel a well-deserved donation!

[@lordowusuafrifa546]

Emily

[@lordowusuafrifa546]

Thus really exciting

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So this is my first comment but I'm a loyal subscriber and viewer. I just wanted to share that you have a way of calming down whatever anxiety or doubt I may have whenever new material is introduced. Your passion is super admirable and soothing, not to mention helpful and understandable!! As a current student in A &P II, I often get anxious bc it's been quite a while since I've been in school. Just knowing that I can count on ninja nerd to explain it in a thorough manner, makes me feel at ease and overall, more about the material. I tell everyone about this channel when asked how am I understanding the material!! (Even when they don't ask)😁 To say I love your channel is an understatement...I LIVE BY YOUR CHANNEL!! Untouchable!

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Same here :)

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Same😊

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7

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Same here!

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Hello I’m a medical student from Saudi Arabia and I just wanted to say THANK YOU so so so much. Keep up the good work man, you’re a life saver

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I’m not a medical student, I’m a fitness trainer and when I watch your video I feel I’m watching a movie which is holding me till the end and I overjoy after learning it well by the end. I must say your teaching skills are by far the best I have ever encountered. Keep it up, I hope this family grows bigger and bigger.

[@emilywallie5859]

So I've been trying to understand this for 4 years and this has been the most useful 48 minutes of study ever. You guys are incredible.

[@oumamaderkaoui6130]

Me too 😂

[@sebastianflorez2347]

As soon as I get my first paycheck, i am gonna donate it entirely to your channel. You deserve to be the better paid teacher in the universe and I hope one day I can be as good as you in teaching

[@suvidhadere3422]

"Dont u dare laught at me, I m short" Adorable !!! 😊 I love ur videos, keep up d good job. Thank u Ninja nerds!!!

[@mirunalevarda6741]

I can not express my gratitude to you enough. I'm a medical student in Italy, I've attended a ridiculous number of lessons, I've read books and notes, but your 48min of video taught me more than everything else. It's actually quite amazing that you are sooo good at explaining that I was able to understand everything, even if it is not my main language.

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Your passion for the topics and the simplistic approach that you use to explain everything (in detail) is incredible! Every time I start a new topic, i search for your videos on it first! You are doing a great service to all the struggling medical students out there sir! :)

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You are an AMAZING teacher. Thank you for your time, and content. Greatful I've found your channel!!

[@jacquim5134]

You are so amazing! I am so glad I found you early in my med degree. Your knowledge is just incredible and your ability to teach it to others is unparalleled! Thank you for doing what you do

[@Misscellaneous_]

not sure if you're a PhD but i really hope you're already a professor or on your way!

[@david9840]

He's a PA (physician assistant). The fact that people thought he's a doctor or PhD speaks to how well-trained PAs are.

[@Misscellaneous_]

@@david9840 totally! Been awesome to see this grow. Saved me in my kin degree. Better instruction than most of my professors. At least for my style of learning

[@david9840]

@@Misscellaneous_ Agreed!

[@millifire693]

9:28 this keypoint was asked more than 4 times in the same exam...the examiner was just changing the way of asking but that was the key idea, thank you so much ❤❤

[@SnapStats247]

As i finished watching this video it felt like for the first time I learned something. There is surely no other way to teach better. I have been through so many lectures but something was there which was not adding up like how nodal cell connects with the contractile cells but now when I know it feels exactly like when you finally acquire the knowledge you have been trying to get from years back. Please don't stop making videos. I am doing Bachelor and counting on you.👍👍👍

[@sv9821]

I was unable to understand even a single word in textbooks and hours of med school lectures. But just 48 min of this masterpiece made everything clear as crystal! Keep up the good work! 🔥

[@saifu8578]

You teach so painstakingly bro and then all your content is here for free. That’s a huge act of kindness

[@calebc4471]

This video is honestly a lifesaver, I was so confused about the intercalated discs and the sodium/calcium/potassium channels but now it makes perfect sense!! Thank you so much :)

[@hamsaahmed7797]

Really appreciate your devotion! lots of love and respect, thank you!

[@JitterJuice]

Thank you so much for doing these lectures, the quality of your teaching is incredible. I've learnt so much!

[@user-zo7ie2ut5w]

I cannot express how much you have changed my life... I don't even have the right words for expressing my gratitude, you are amazing , I wish I have had teachers like you, how much I would enjoyed the lectures if that was the case

[@heatherduncan5826]

I cannot thank you enough for these videos. This is brilliance and I will support you. You are hand’s down the best teacher I’ve ever encountered. The breadth and variety of expertise in your videos, your enthusiasm and energy. I’m on here all the time. I used to get so worried if I had a mediocre teacher. Now, I’m like “no worries, I’ll go on Ninja Nerd”. :) Thank you so much. You are a brilliant person. Legit brilliant. No exaggeration. Just the truth. 🤓👍🙌

[@sriramjanarthanan]

Even after attending tons of lectures and studying tons of notes...... these 48 mins made me really understand the concept very well. and you keep us concentrated very well brother. Love from India.

[@UnZipped55]

"oh shoot, they hit threshold potential" had me in tears

[@AkashKhan-wi1ie]

I had so much difficulty understanding the cardiac action potential & the pacemaker potential during my 1st year. This was the best explanation I've ever seen on this topic!

[@KadeSuchan]

OMG you're awesome! I'm in school to be an MA. I want to continue to nursing and end up as a CRNA. You bring such enthusiasm and interest to these subjects! This is well above my current educational needs, but you've made it interesting and fun, so I just keep watching!

[@orientalflower1900]

I love your videos! You are very knowledgeable and a great teacher!

[@danielj.ortiztorres3169]

OMG bro you are a genius for teaching us this great! This is my first time watching your videos and I can tell I have never got it this clear from a lecture, you connect all the dots in one and i like that, I am from Bolivia my native language is Spanish and I totally understood your whole video dude, Keep doing this great work! once I got money i will support you as much as possible. Thank you!

[@SAYGUTZ]

I love everything about Zach but my most favorite part is how he appreciates the body processes/anatomy and then describes them as "amazing", "cool" and "BEAUTIFUL" AND you know he means it!! THANK YOU FOR EVERYTHING NN!!

[@thehooligancrew3107]

God bless you man. I hope you have an amazing life. Spent 3 weeks learning all of this but you summarized it so well.

[@93shreelakshmihs]

YOUR 48 min videos saved my many hours. Thank you so much

[@Sunshine-zp8eg]

Thank you for explaining everything that i didn't get nd just learn them up to pass my exam. With ur video everytime I realize why I choose this field 🥺🥺🥺

[@anfalmadaci9888]

You are the BEST professor ever! Thank you so much for your efforts! And just so to let you know you raised lots of today's doctors and the future doctors too.

[@aliciaflores9936]

Thank you for explaining the material in a visual understanding way. You have helped me WAY more than my actual physiology teacher during this pandemic. I'm a visual learner and your explanations and pace is very helpful.

[@ashleyzuva3289]

you remind me that everything is going to be okay! thank you!

[@extrachannel7643]

you truly an incredible person , such an awesome explanation to this subject , keep it that way bro ❤️

[@NinjaNerdOfficial]

+Extra Channel Thanks for the super nice comment, glad you enjoyed!

[@zacheryknudsen8553]

I am almost done with my bas in echocardiography and vascular ultrasound. I cannot thank you enough for your videos which have helped me better understand the heart in a multitude of different ways. I am taking my ECG exam next week as well and you have definitely helped me understand interpretation a lot more then I ever have. Thank you!!!!!! Will definitely be donating to you once I complete my externship and start working. PS some sonography/echo videos would be awesome!

[@yvngxsamy7129]

I can’t thank you enough for what you’re giving the students. Your lectures are a life saver 🙂 hats off to you

[@lilvic1798]

I'm in my first semester of vet school right now and your videos are a lifesaver!! You make me feel so much more confident about the material I have to know for class! Thank you so much!!

[@mash3103]

sameee

[@dentfortune7271]

“These beautiful gap junctions” oh so beautiful 😄📚❤️

[@mandrithysa3457]

third year medical student and i have my cardiology/pneumology exam 2 months later, your videos are the best Zach. Thank you so much, we really owe you a lot.

[@Radmxray]

Love this guy. I used his videos to study for a Vascular Registry. I am now using them to study for RCIS cardiac Registry test. He's amazing and explains everything so well.

[@calebquinton9265]

My dental school Biophysiology professor lecture’s consist of slides with screen shots of ninja nerd videos and a link to ninja nerd videos for us to watch instead of him lecture us lol.

[@katerinagoffigan4367]

Hi, your videos are simply amazing and I have learned a lot from them! I wanted to ask if you have ever considered posting a link for your "empty drawings" , where we can print them out and write on them as you go along the material? Thank you for your time!

[@megveera3001]

I wish you could get a reward for how well you teach oh my god everything is so easy to understand because of your videos!

[@jessicawinkowski2345]

I work in Telemetry and this content is awesome, I know a little more by listening to your content then I did reading some study material. I hope this page continues. Thank you.

[@sethperry2641]

Great video, however at 5:20 it is mentioned the SA node sets the pace at 60-80bpm. This is incorrect. The SA node spontaneously fires between 100-110 bpm. The vagus nerve and other physiologic factors are responsible for bringing it down to what we consider normal with is around that 60-80bpm.

[@vanajeeth96]

It's 60-100 😴 please verify from other sources too

[@ime13543]

Videos are just perfect, my hat's off to you for existential knowledge (coming from an MD). This should be included in high school and even med schools. If you are reading my comment, just a suggestion and a wish, once you are done with the drawing, could you do a freeze frame of a board so we can take a screenshot, or upload a photo of a board and add a link below the video? That would be great for us to keep in the gallery for repetition. Thanks and keep the good work!

[@NinjaNerdOfficial]

We are currently in the process of drawing each and every lecture we created to be added to our upcoming website. Thanks for the great suggestion!

[@ime13543]

Glad to hear that, looking forward to it! Keep the good work guys. Greeting from Croatia :)

[@richardcampbell5579]

I like your style. You have an enthusiasm for teaching that I am not seeing in other teachers. Thank you. You have a rare gift.

[@Mariondtz]

I want to express my gratitude... Thank you SO much for your videos. I was a nurse in France and I am now studying paramedicine in New Zealand. Your videos are amazing, you are talented, thank you for sharing your knowledge and help us to become good clinicians.

[@vanessazz]

im gonna comment on all the videos im watching bc you're saving my life THANK YOU

[@eunicekapweya6507]

I hit the subscribe button after listening to you. That means you made me understand,now am searching for your part 2,

[@ugokwepeace4821]

Before this video, I had no excitement whatsoever in studying the heart. But now, wow! The heart is really amazing and easy to understand. Many thanks to you guys. You rock!

[@chahatsachdev7260]

Thank you sir !! I cannot repay the debt of gratitude i hold for u in my heart !!! May you be blessed with all what u wanna acheive ..my prayers and wishes are with u sir

[@akashmenanmenan50]

Yo bro u made my day, Iam started liking cardio now ❤️✌️👌💐🎉🎉👋👍thanks broi!!

[@eemanbintesaqib3148]

No words can explain how thankful we are for your lectures!!!

[@bobbieshaw6583]

I wish I would have found Ninja Nerd in AP1, WOW I am in AP2 and just now found these videos. This is SO thorough and makes total sense after watching. Zach you do a fabulous job making sure every detailed is explained and makes sense, THANK YOU you Rock

[@diveshjairamdasani6739]

Referred 3 books for this concept, read more than i could, and your 48 mins video was like damnnn such satisfying , each concept just got engraved in my brain! THANKKSSS A TONN BROTHER! THERES NO SUCH AWSOME VIDEOS LIKE YOU MAKE ! just keep going we need such people to become great doctors! I JUST DONT HAVE WORDS TO THANKYOU ENOUGHH

[@latinboyyy305]

Freakin Awesome video!!!! I hate not knowing every detail, even though for my profession (med-surg nurse) I don't have to, but I still WANT too lol. Thank you.

[@chell0chii]

you deserve more exposure

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Salute to this man how simply he explains such complex topics ❤❤❤ love from India 🇮🇳

[@imhidingasecret]

i DIDNT REALIZED I HAD AN EXAM DUE AT 11:59 TODAY AND I THOUGHT I STILL HAD TIME TO STUDY SO I PUT OFF STUDYING THIS CHAPTER FOR NEXT WEEK BUT NOW I NEED TO CRAM FOR THIS EXAM AND IM WATCHING THIS AT 3X SPEED TRYING TO GET AS MUCH INFO AAAAAAHHHHHHH

[@shreyaghoshplus]

"what are these little invaginations? trust me its a word, I know" LOL

[@hamzamohammed2348]

I can't thank you enough, God bless you 😭😭😭😭😭

[@adivider6596]

I am obsessed with your videos!!! You are a really wonderful teacher... You literally save me time after time passing my exams. Really helping me going through Med school. Please keep doing what you do! Thank you so so much... Your fan from Israel :)

[@aymeric_L]

I just love it. Every new video I’m watching makes me love even more the topic, not to mention understand it !!! Your channel is awesome. You guys are the best and I don’t know how I’ll do without your explanations. Probably gonna get some merch soon to help you out because you definitely deserve support and recognition for this beautiful work of art and teaching. Thank you so so so so much !!!!!

[@MrSouthsideMuscle]

I wasn't aware so much stuff goes on for a heartbeat

[@samiliaa1531]

Thank you so much for what you do. You are amazing.

[@NinjaNerdOfficial]

+Samilia Asare awesome I'm so happy we were able to help!

[@kimnamjoonstrash9571]

Thank you for putting so much effort in your videos. Your explanations of complex phenomenons make it very easy to follow and understand. I struggled with this topic for 2 years of school and I finally understand it because of you. The breakdown was phenomenal. Thank you so much for teaching me and all the others.

[@YoovrajShinde]

This is really awesome. I had no knowledge and no background in biology, but still could understand most of the stuff. Thank you so much for sharing your knowledge to everyone !!

[@Faustian_Bargain_Bin]

Incredibly helpful! I'm a first year med student and I was struggling to understand my prof's powerpoints on this topic.

[@humanbeing3177]

Oh dear, you are a masterpiece of the Almighty

[@sy1511]

Bro, this is basically Costanzo. So clear, yet thorough. Thank you. Keep up the good work, man.

[@salomelau]

I'm now regretting not paying more attention to cell physiology class >< I had to stop a few times in the video because there was so much information! But I really enjoyed this video because it made me realize that the heart truly is a specialized organ and that no matter how "hard" the material is, I still want to learn more about it! Thank you for helping to explain cardiac electrophysiology in a way that I can understand them!

[@donnathomas17]

Thank you master

[@jalisabrookins7686]

Ohmg, he is so handsome. And his knowledge just enhances it.

[@bethanierussell5115]

Thank you for making these videos. You do a better job than most of my professors. Please keep making videos like this!

[@laurasamander4152]

I really cannot thank you enough for all your videos. Upcoming second year med student and you really have saved me!

[@Monta87b]

Thank you so much I wish my professor was like u, she is only reading from the presentation without explaining anything 😒

[@Alex_0341]

Spiker_87 same here, I have to teach myself

[@REL180685]

Great job man!

[@NinjaNerdOfficial]

+אריאל יודקוביץ thank you so much we really appreciate your kind positive feedback

[@malicdemaltheamariel.6144]

I got drained from reading, and so this helped me so much, thank you!

[@AsraJahan-ge4oc]

I just am surprised by how much he is in love with the physiological mechanisms and keeps appreciating them. I so admire his passion so damn much❤

[@GomelSkychenal]

If I want to learn something which I did not understand in lecture just type topic + ninja nerd

[@ratdogandthevoid8812]

Notes from the video because I got confused by the order of things: General Flow: SA Node → AV node (via internodal pathways) → AV bundle → L & R Bundle branches (branches of the AV bundle) → Purkinje fibres. Notes about the SA & AV nodes: SA Node: creates the sinus arrhythmia (60-80 bpm), pacemaker of the heart Connects to and can stimulate the left Atrium via the Bachman’s bundle. Stimulates the right atrium via the internodal pathways. Stimulates the AV node via the internodal pathways. AV Node: An AV node can interact (can be stimulated by )with the bachman’s bundle. The AV node branches into the R & L Bundle Branches within the interventricular septum which then stimulate the heart via the purkinje fibres. How nodal cells communicate with contractile cells Nodal Cells: RMP of about -60mv Na+ leaks through leaky “Funny Sodium Channels” which then lowers the MP to -55mv Voltage-gated calcium channels open at -55mv, causing an increased inflow of calcium, and for cations to gather within the cell, raising MP to -40mv. -40mv is the threshold of the nodal cell. Once threshold is reached, there is a dramatic increase in Calcium (threshold activated the L-type Ca+ Channels causing an aggressive increase). MP is now +40 mv, depolarizing the cell. Gap Junctions: In order for the nodal cell to share current with the contractile cell, the ions must travel through gap junctions. Gap junctions exist between the intercellular space, connecting the cells together. Desmosomes hold the gap junctions and cells in place so that they don’t stretch apart. Gap Junctions + Desmosomes = intercalated discs. Contractile Cells: RMP of about -85mv. Inflow of positive cations results in an increase in MP, activating threshold. When threshold is reached, NA+ voltage gated sodium channels open up and release Na+ drastically increasing MP. Cell depolarizes, positive charges move across the cell in a wave. MP gets to around 10+mv (meanwhile very few additional CA+ channels open and allow CA+ to flow in), so the Na+ channels close. K+ channels open at the same time as the Ca+ channels, but the amount of K+ leaving the cell greatly exceeds the amount of CA+ entering the cell, causing a little drop in MP (around 0mv). CA+ becomes more active at 0mv while K+ are still leaving the cell, causing a plateau at 0mv. The Inflow of Calcium causes Calcium-induced Calcium release. Some Calcium ions to receptors on the Sarcolemma, and additional calcium to be released into the cell At a certain point CA+ close, and CA returns to the sarcoplasmic reticulum (either by moving up the concentration gradient and using ATP or swapping places with sodium). Ca+ is pumped out of the cell Na+ is pumped out of the cell Potassium channels continue to release K+ and the cell is at rest. The nodal cell allows for Na+ to leak in… and the whole cycle starts over again.

[@muskan5047]

Thanku so much i needed this:))

[@Bubagigant]

This is by far the best lecturer on KZbin!!! Thank you so much!!!

[@JenniferPerkins907]

I love all your videos. You're very clear, knowledgeable, worth listening to.

[@tiffanyjazlene7969]

"What is this little invagination?.. Trust me it's a word, I know" I facepalmed myself lol

[@jessicalynn4062]

invagination - "trust me it's a word, i know". lol!

[@ILUVHOTBOYS1]

Thank you! I'm an M1 in a DO program & ur visuals & sensical explanations are saving me!

[@shirley6249]

I have practiced nursing and enjoyed. Now I’m experiencing EDUCATION from my CARDIAC challenges and your beautiful thorough explanation THANKS for great explanation.

[@drparks1061]

"Trust me, it's a word..I know.."

[@platypusguineapig]

Anybody have an exam tomorrow 😄

[@shockinggamers9791]

Tomorrow is my end of year 1 med school exam and I’m watching this now!!!

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You are AMAZING! The best teacher! I don’t know what I would do without your lectures.