Cardiovascular | Cardiac Cycle

Official Ninja Nerd Website: ninjanerd.org
Ninja Nerds!
Join Professor Zach Murphy in this lecture where we discuss the cardiac cycle along with clinical correlates that can occur. We hope you enjoy this lecture and be sure to check out all of our social media pages and ways to support us below!
References:
● Le T, Bhushan V, Sochat M, Chavda Y, Zureick A. First Aid for the USMLE Step 1 2018. New York, NY: McGraw-Hill Medical; 2017
● Mancini MC. Heart Anatomy. In: Berger S Heart Anatomy. New York, NY: WebMD.emedicine.meds....
● Hill M. Cardiovascular System - Heart Histology. embryology.med....
● Standring S. Gray's Anatomy: The Anatomical Basis of Clinical Practice. Elsevier Health Sciences; 2016
● Leslie P. Gartner, James L. Hiatt. Color Textbook of Histology. New York (NY): Grune & Stratton Inc.; 2006
● Maceira AM, Prasad SK, Khan M, Pennell DJ. Reference right ventricular systolic and diastolic function normalized to age, gender and body surface area from steady-state free precession cardiovascular magnetic resonance. Eur Heart J .2006; 27(23): p.2879-88. doi: 10.1093/eurheartj/ehl336.
● Marieb EN, Hoehn K. Anatomy & Physiology. Hoboken, NJ: Pearson; 2020.
● Boron WF, Boulpaep EL. Medical Physiology.; 2017.
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#ninjanerd #cardiaccycle #cardiovascular

[@kennethbutler9164]

You’ve done it again my good man. You’re a master teacher. Thank you

[@yasminali7578]

it's honestly amazing when you find someone who actually cares about what they are explaining. I always used to wish I had someone to explain it to me like this.... then I found your channel. A comment section isnt enough to express how much i appreciate your videos...... please continue to explain these concepts with the care that you do

[@NinjaNerdOfficial]

+Yasmin Ali thank you so much for your kind words they mean so much! I'm so happy we were able to help!

[@sanaali2805]

very true ...his flow makes concept easier

[@wedneyanugwo7847]

@KZbin Account the aortic pressure is always greater than the ventricular pressure due it's total peripheral resistance which is dependent on the tone of the arterioles........ so what ever the preload (end diastolic volume)is....it still have to generate enough pressure through contraction to overcome the pressure in the aorter which is managed by the TPR....so if the arterioles are constricted the tpr Is more and then ventricles need to contract even more to overcome the pressure in the aorter..... And for the pulmonary pressure to be more than the right ventricular pressure there should be some kind of back pressure from the left ventricle which Is due to systolic or diastolic failure.....so I think that's the only way the pulmonary pressure pressure can be more than the right ventricle pressure.its too much to read but I hope I could help you a bit

[@noahsamassa8974]

Ala

[@abeerchowdhury8510]

@@youtubeaccount7318 pressure = force / area. Pressure shares an inverse relationship with area. Smaller the area that the force is being applied upon the greater the pressure.

[@heyheypimpin]

Dear ninja nerd, I'm buying your merch to support you !!! Cannot thank you enough for all you do, please continue to keep up the good work, all us med students greatly appreciate you!

[@NinjaNerdOfficial]

Thank you so much!!!

[@jannatunnahar4084]

Thank you for making anatomy easier

[@myrawhues]

I'm addicted to this channel 🥺

[@clairedelune4389]

This video was amazing!!!!!!!! I thought i would never learn!

[@jyotik7632]

Perfect diagrams. Apt information. Great Content. Thnks for your lecture vedios.

[@laurabartley7759]

this is fantastic!

[@sabariaz6121]

Very helpful lectures.🤗🤗🤗🤗

[@NatEmily]

Thank you, I'm not really a good science student, but your explanation helps me a lot to understand what's going on in my physiology notes😂 otherwise I'll be understanding it the wrong way hahaha

[@neenajohnson8190]

Thank you

[@atheer167]

JUST AMAZIIIING

[@bnfgh123]

I don't think the QRS complex appears in the mid to late ventricular systole. The QRS complex has to occur so that the systole can begin (the depolarization causes the contraction), and therefore the QRS complex appears right before the isovolumic contraction starts.

[@RoyalCaoCao]

Had to re-watch this entire video twice to fully understand and grasp the concept. But my professor thinks he can mumble it through in his 5 minutes slides and expect me to know it all.

[@BLOODM00N13]

mine didn't even explain everything, she said we should know all this already, idk where she thinks we should have learned this, but we hadn't and it sucks, but i'm glad this channel exists otherwise i'd be lost by now

[@toobasiddiqui3653]

Which university buddy?

[@piyushsumera1433]

I am baffled to know why this channel doesnt have that many subscribers and views on Videos likes these are very less..I guess people dont want to learn the things in details and want to just mug up the things after learning from short videos which other numerous channels have..But I guarantee Nobody can come close to this channel as far as Physiology is concerned.

[@NinjaNerdOfficial]

+Piyush Sumera WOW!! This means so much thanks for the kind words!!!!

[@tajosman6258]

This didn't age well

[@piyushsumera1433]

@@tajosman6258 why??

[@ASalfity]

Yeah, I love the detail oriented nature of this channel. While I also watch other channels as well I come to this one for greater details. More details and more information is better, please, do not become like those other channels that just briefly summarize everything.

[@abhilashpanigrahi6098]

@@piyushsumera1433 cuz a lot more people are seeing this now

[@noellesimoes]

my professor could never

[@charmainesayi4826]

joey :] same here😌😌😩😂😂

[@k-addict8703]

Periodt 😂

[@presleylamb7246]

My professor pronounces it "diastol" and "systol" he also says semiluminum valves.... videos like this are my only hope.

[@kneelbeforedean8189]

Semiluminum valve 😂😂 lmao

[@naturaltalent4975]

@@presleylamb7246 🤣🤣🤣

[@johnclark4476]

You don’t need subscribers sometimes you need pray from medical students in terms like May God bless you with health,wealth,joy,laughter,prosperity and much more...

[@naaengmann2117]

What kind of teacher is this?? Why am I paying my school when i could be paying you. Sir, I must say you are an excellent excellent excellent teacher. I don't know what I would do without you and your wonderful videos. Thank youu soooo much

[@ArundhotiRay]

I do regret why I didn’t found this channel earlier. Thank you so much professor, for being such a wonderful teacher😊

[@SoresaAbdisa-pc7ik]

waw Amazing 😍

[@ASalfity]

Brief Table of Contents: 0:10 - Cardiac Cycle Definition ( ~ .8 Seconds) 1:05 - Mid to Late Ventricular Diastole (diastole = relaxation) - (period of ventricular filling) - 5:20 - P Wave EKG 6:35 - Isovolumetric Contraction - 11:20 - “Lub” (S1) 12:05 - Mid to Late Ventricular Systole - (ventricular ejection) - 16:30 - QRS Complex EKG 16:50 - Isovolumetric Relaxation - 21:40 - “Dub” (S2) - 22:50 - T Wave EKG You may wish to add this to the description or create your own more detailed version. Thanks for these videos.

[@mtwins2250]

Wow thank you🙏🙏

[@shubhamyadav7311]

Thanks 🩺🧬🙏🙏🙏🙏🙏🙏

[@lacatrass]

up

[@samanthastephens9443]

May your pillow always be cold and your belly full

[@dayennyd1062]

Things I've noticed. I learn so well with pictures and step-by-step explanation that this is sooooo much better than the power points we get in medical school. I feel like i learned so much!! Wish there was a wiggers integration with this but I can now look at one (using your EKG videos too) and get it regardless. THANK YOU THANK YOU! YOU'RE SO AWESOME!

[@hariskhan-xj4wk]

which med school u went

[@abdullahshaikh8366]

If the AV valves are closed then how did the pressure rise to 120mm of Hg ??? Like no more blood is entering

[@Kishan_sonagara151]

Cardiac muscle contraction:- once the single fibre is contracted, then it is connected to whole ventricular musculature by gap junctions and intercalated disc. So, it contracts as a whole.

[@Williamwilliam1531]

I hope over the next 20 years, Medical professionals everywhere will be showering you with well-deserved donations. I hope people eventually realize - by measure of suffering alleviated, you are one of the most heroic and legendary creatures to ever grace the earth.

[@anorexshynervosa]

I'm gonna be a doctor because of you.

[@mikepenalosa9589]

You are the reason I can continue my career goals and make my family proud. You are also the reason why humanity will receive quality healthcare. Thank you.

[@MrFares123451]

This channel is better than my whole UNIVERSITY!!!! THANK YOU ❤ , and please don't stop making amazing videos like that

[@kneelbeforedean8189]

Yea it’s fun learning here, i hope when I enroll in any university I already know most of the things 😁

[@amandawilliams6498]

I have had the hardest time understand the cardiac cycle in it's entirety. I watched your videos and you are great at explaining clearly, so those of us that "just don't get it, actually finally have our ah-ha moment". Thank you so much!

[@23hareemmalik76]

Hi there. I know it's late. But just here to tell you how thankful we are for the channel. You have amazing way of explaining things. Keep blooming 💖

[@katiebernard2514]

I have a question. From my understanding your ventricle and aorta pressure are your a line pressure. So why is your a line pressure not fluctuating with the low ventricle pressure like before the pressure increase pushes it through the aortic valve? I work in a hospital and work with A-lines often I just don't understand why they wouldn't be fluctuating with the pressure changes.

[@ElliePearl]

Teaching is an ART FORM! People assume that just anyone can do it, and it's not true. This video was excellent and so informative. It was an example of great teaching. I hope one day more attention will be brought to the importance of fine teachers and that they get paid more, because they truly make all the difference. I'm so grateful for this video. Thank you very much!

[@mariamdean6369]

F MY DENTAL SCHOOL, YOU'RE MY REAL TEACHER😭❤️

[@sebcodestheweb9385]

Your teaching style is brilliant, I am impressed by how you manage to explain this topics so intuitively and easy without oversimplifying it and keeping it thorough.

[@sander_bouwhuis]

You explain it EXTREMELY well/clearly! Especially the fact that you leave a tiny pause before you reveal the answers so that we as the viewers can come up with the answers ourselves. That is REALLY fantastic as it means we can actively participate instead of just passively view the material.

[@lacatrass]

guys, the cardiac cyle took 0.8 seconds???

[@richarddekoa7657]

I'm not one to comment on YT videos but this video right here Sir has prompted me to do so. The explanation was clear and easy to understand LITERALLY!!! Mad love from a student in Fiji who is in Med school. Vinaka

[@NinjaNerdOfficial]

Welcome to the Ninja Nerd community! Check out the Discord (if you haven't already).. It's free and connects you with other community members from around the world to talk with/study with. - TG

[@hannahsteff9472]

Thank you so much for breaking this down and displaying it in such an easy to follow manner. Trying to learn this by just reading giant chunks of textbook was making my eyes crossed! So grateful for your channel-especially during online only learning.

[@zulalerdogan40]

I'm a med student from Turkey. I watched your cranial nerves videos and they were very beneficial for my committee exam. Now I'm watching this 😃 You're very perfect in teaching 😁 Please keep going on for us 👏

[@maheen97]

God bless you - can't imagine doing medical school without you. You can explain things better in 20 minutes than professors can't do in hours!!!

[@hajerafirdous7513]

I must say yaarr you saved me 😭😭!!! Now I can finally prepare for my exams A big thankyou 😊

[@lifegoeson4904]

Hlo sir, I am a medical student who learn more on your video than in my classroom. ❤❤we support you always and we need more content like this.. ❤🎉

[@Rh92887]

I would pay to get subtitles on your videos! Very nice job!

[@DrAziiiiz]

Medicine is fu***ing hard but at the same time is totally fun! What " Slowly " Actually means is that it's a split of a second ! All the Cardiac Cycle happens every second if you HR is 60 ! That means if you're playing Football for instance You're likely to have 120HR or above > thus every phase of this cycle happening in milliseconds ! That's just insane!

[@rutvin8763]

GREAT video. One small issue I had was the timing of the EKG part didn't fully make sense to me. Specifically, the following points: - During ventricular diastole, there is the passive filling stage you mentioned wherein the high pressure in atria and low pressure in ventricles causes 70-80% of ventricular filling. But the remaining 20-30% gets transferred to the ventricles by atrial systole, which would happen during the *PQ segment* on the EKG since it follows right after atrial depolarization and is the delay between SA and AV nodes firing. - Also, QRS complex involves the depolarization of the ventricles, but no contraction happens yet. Isn't it the ST segment during which the ventricles are actually contracting (isovolumetrically at first, followed by ejection)? I would've had the EKG for phases 3 and 4 on your diagram as ST segment while the QRS complex would be at the junction between phases 2 and 3.

[@joshm3519]

This is amazing stuff! This helps me so much going into Cardiac ICU and knowing the basic and fundamentals - awesome, thank you!!

[@narges8438]

I cannot thank you enough for your effort and for making such an incredibly helpful videos 🙏 ❤️

[@maryborges6996]

Your videos get me though nursing school. You teach me more than my professors do lol 😹. Please keep uploading pharmacology and physiology videos!

[@myname2496]

This man is anointed by God to preach the gospel of pathophysiology!

[@ChillNightDriveBeats]

I'm a medical assistant student and right now my school is going through a transition from one teacher to another. Unfortunately the new teacher is not working out well at all. You are so so helpful to me learning , I just had to express my many thanks to you and your videos. I'm learning everything I need to learn . I appreciate you!

[@047-aparnadeepgupta6]

Oh God!! How could I forget about tomorrow's viva.. it's already 11:55 pm ...I'm gone now....oh wait I have ninja nerd... that's more than enough ❤️❤️❤️ thank you ninja nerds😘😘

[@kyla1602]

This man is a national treasure.

[@naaengmann2117]

Wow.. the explanations are perfect. You are a superb tutor. Wow.. Just amazing!!!

[@shrutisingh6556]

One of the best teachers out there ! Thanks for ur hard work sir ! ✨✌️

[@annachantalieva7510]

Thank you so much! I survived AP I with great success thanks to you and hopefully AP II will be successful as well.

[@alexisteja9920]

Wow! Thank you so much for this! You are very inspiring, Sir! Your passion for teaching translates on how much you want your students learn from you. This 23 minute video is a life saver. Thank you!!

[@SulemanKhan-eh6jm]

I am definitely going to give you my first salary after i become a doctor...

[@arfandibayuramadhan9990]

LMAAOOOOO

[@gofoodiess8030]

Thank you for this ~ Omar Hegab

[@joeytallakson2016]

Taught me in 24 min what my med school phys professor taught in a week

[@blaster_7719]

same

[@MohanRam-zl4jq]

Thank you sir for the beautiful vedio

[@jeanniechan6237]

I have been reading my notes over and over again for an hour trying to understand nth but now I understand everything in 23 mins. Thanks so much for your teaching you save our lives!

[@Dr-Hafsa12345]

you just cleared my all doubts , early ,i was very worried about my exam but then i found you video thank you doctor

[@1987farri]

Your videos have helped me so much! I’m so glad I stumbled upon them! I understand everything so much more after watching your video! Thanks so much!

[@raveenajaved8708]

Ah! Bless you. You have made learning easy for us. So much respect for you!

[@architasaha8917]

You are gifted brother, stay blessed always.

[@louismarquez9562]

I wish we had pictures of the board after he was done with his lectures :(

[@karlacasillas3596]

I thought I would NEVER understand this! I completely know this whole cycle by heart now thanks to you !!! Thank you for all yours videos.

[@ummenisa]

Thank you very much Sir for making physiology much simpler for us. You’re better than most of our college professors Love from Pakistan 🇵🇰

[@sharmihaque4769]

Zack we need some subtitles on some of your videos! xx

[@tiffanypapandrew3860]

Could you please tell me which videos would help me the best with the ARRT cardio vascular interventional boards I am a radiologic technologist studying for the CI boards

[@adrianaharisya1257]

Thank you so much for this explanation!! You're a great teacher

[@TS-oi5uf]

Unreal video. Thank you so much!

[@AliHaider-mj2dy]

I is really helpfull , I have test tomorrow and this help me to recover and learn all the things.i read many books like guyton and hall and many other books and pdf but this vedio help me alot .thanks you sir for this great lecture

[@alexaorozcorodriguez126]

THANK YOU BEAUTIFUL MAN!!!

[@juliahildabrant7803]

You have helped me understand more topics in both my anatomy and physiology 1 and 2 classes, than I can even explain!! It is clear you care about what you're teaching and you do it in a way that gives enough detail but also is simple enough to comprehend. Thank you so much!!!

[@heavengarden4235]

You are the best teacher 👨‍🏫 I have ever seen

[@jaredpadgett3836]

Hi Zach! I am currently in Medical School. Our professors are teaching the cardiac cycle in 7 phases now instead of 4. Is there any way you can update this video to accommodate these changes? Thank you!

[@josefernandomora1132]

The blood return to the left Atria for the pulmonary ARTERIES no pulmonary veins.

[@user-tq7dt5vt4w]

I never comment on KZbin videos but this is so great. Thank you so much for this gem!

[@DanishTUTGamer]

where is the graph you were talking about

[@georgiamoncivais2330]

You are absolutely AMAZING with how well you thoroughly explained this entire process! Thank you so much.

[@chickendeener]

I think you used to tutor me in my local community college! I'm pursuing my master's at the moment and you are helping me again :) thanks for this video!

[@Junior-su6bx]

THANK YOU SO MUCH! I was feeling really overwhelmed after our first exam and dove into all of the heart/Blood vessel information. Your videos are really well made and go hand in hand with the notes provided!

[@mabelidove6813]

Did he say on average it takes .8 seconds?🙊 Our hearts are so amazing, always working nonstop till our last breath 💓

[@lu35253]

I am brazilian! I am studying medicine in Paraguay and you are saving me in all posibles ways. I want to be a teacher and you are a such inspiration. Thank you is not enough. God bless you and your team.

[@AjayKumar-ng9cf]

Thanks sir for making such amazing videos and making physiology easy for us😊😊😊

[@Flamma1205]

Hi, awesome video! But I have a small question, in the beginning of the video, Prof. Zach says that during diastole of the atria, 70 to 80 percent of the blood will drain into the ventricle passively, but what confuses me is that in the cardiac cycle graph, during the atrial diastole (at the very start) there doesn't seem to be any increase in the volume of the ventricles. Can anyone clear this up for me please!? Thanks!

[@nkhomafrancis.7456]

Have been following these explanations since the day I start my studies and it's helping me a lot ❤

[@maduekehenry6200]

Med students saviour---->ninja nerd

[@pvratliff4]

You are an Amazing Scientist and Instructor. Thanks for Everything!!

[@shandani7215]

If blood drops passively by gravity, what will happen if I am upside down. I have one of those inversion beds. I like to hang upside-down for up to 20 minutes at a time. I'm still alive, though.

[@muhammadnabil3390]

I'm super duper late to the party but i'll really appreciate if some one can explain to me a problem i'm having to understand. During mid to late ventricular systolic phase/ ejection phase,when the pressure is greater inside the ventricles as compared to either atrial or arterial then why doesn't the tricuspid & mitral valves open up but only the pulmonic & aortic semi lunar valves open up...? I know the atrio-ventricular(tricuspid & mitral valves) valves will not allow the backward flow of blood from ventricles to atria but still,if the pressure is high in the ventricles & this same high pressure can force the semi lunar valves to open & spill the blood into pulmonary trunk & aorta then why not force the atrio-ventricular valves to also open up...? P.S. Sorry for the lengthy statement.

[@PriyaDharshini-fi3er]

Thank you so so.... Much sir... No words to explain... 😊😊😊

[@dhineshkr2844]

Preparing for my exams...if i got passed definitely u will the first reason buddy..thanks a lot😊

[@naturehealing6786]

Learned so much thank you

[@Watchandcommenti9g]

What's the use of having healthy heart ❤️ when even healthy heart ❤️ can get stroke and heart attack... It's useless ... But what to do... It's all about luck 🤞 if u r unlucky... RIP

[@bhagyaperera5672]

I wanna ask a question , although ventricular pressure reaches near zero in diastole, why doesn't the aortic pressure drop below 80mmHg?

[@RyanWeaver-fp5kq]

Interdisciplinary works and states of coagulation and inflammations and beyond. It’s a lot… workable in patient style.

[@bhagyaperera5672]

Your videos are always the saviors of my university life. Thank you so much

[@Sam48025]

OMG I understand! I've watched like 3 videos and this video was the most comprehensive to me and I can finally understand each step. I also liked the way you drew it out. Very easy to understand. Thank you so much :)

[@integrateapproximate4000]

Thank you so much for your great vids. I was having trouble with this last night but you made everything crystal clear!

[@mariastoynova936]

I'm sorry if my question is stupid but why the blood don't come back to the atria when the systole of the ventricles begin..the pressure in atria is also low..I've read that a small amount of blood do go back and after that the AV valve close..is this the reason the valve to close?