The Cardiac Cycle, Animation

(USMLE topics, cardiology) Phases of the cardiac cycle. The Wiggers diagram explained.
Purchase PDF here: www.alilamedicalmedia.com/-/g...
Purchase a license to download a non-watermarked copy of this video here: www.alilamedicalmedia.com/-/g...
©Alila Medical Media. All rights reserved.
Voice by: Sue Stern.
Support us on Patreon and get FREE downloads and other great rewards: patreon.com/AlilaMedicalMedia
The cycle is initiated with the firing of the SA node that stimulates the atria to depolarize. This is represented by the P-wave on the ECG. Atrial contraction starts shortly after the P-wave begins, and causes the pressure within the atria to increase, FORCING blood into the ventricles. Atrial contraction, however, only accounts for a FRACTION of ventricular filling, because at this point, the ventricles are ALREADY almost full due to PASSIVE blood flow DOWN the ventricles through the OPEN AV valves.
As atrial contraction completes, atrial pressure begins to FALL, REVERSING the pressure gradient across the AV valves, causing them to CLOSE. The closing of the AV valves produces the first heart sound, S1, and marks the beginning of SYSTOLE. At this point, ventricular depolarization, represented by the QRS complex, is half way through, and the ventricles start to contract, RAPIDLY building UP pressures inside the ventricles. For a moment, however, the semilunar valves remain closed, and the ventricles contract within a CLOSED space. This phase is referred to as isovolumetric contraction, because NO blood is ejected and ventricular volume is UN-changed.
Ventricular ejection starts when ventricular pressures EXCEED the pressures within the aorta and pulmonary artery; the aortic and pulmonic valves OPEN and blood is EJECTED out of the ventricles. This is the RAPID ejection phase.
As ventricular repolarization, reflected by the T-wave, begins, ventricular pressure starts to FALL and the force of ejection is REDUCED.
When ventricular pressures drop BELOW aortic and pulmonary pressures, the semilunar valves CLOSE, marking the end of systole and beginning of diastole. Closure of semilunar valves produces the second heart sound, S2.
The first part of diastole is, again, isovolumetric, as the ventricles relax with ALL valves CLOSED. Ventricular pressure drops RAPIDLY but their volumes remain UNchanged.
Meanwhile, the atria are being filled with blood and atrial pressures RISE slowly. Ventricular FILLING starts when ventricular pressures drop BELOW atrial pressures, causing the AV valve to open, allowing blood to flow DOWN the ventricles PASSIVELY.
All images/videos by Alila Medical Media are for information purposes ONLY and are NOT intended to replace professional medical advice, diagnosis or treatment. Always seek the advice of a qualified healthcare provider with any questions you may have regarding a medical condition.

[@Alilamedicalmedia]

Love this video? Check out our course "Cardiovascular Physiology" made entirely with videos like this (no watermark, no ads): Students, click here: www.alilaacademy.com/courses/cardiovascular-physiology-for-students Teachers, click here: www.alilaacademy.com/courses/cardiovascular-physiology-for-teachers NEW: Now you can also get access to our courses with our KZbin channel membership (Academy Access levels)

[@CarolineBay]

4 minutes taught me what a 1 hour lecture couldn't... thank you!

[@imran-6012]

Lol

[@pubgliteshortvideos6095]

Really

[@YasirKhan-jo7rd]

Really lol

[@sofiaguerrero0969]

Lmao ikr

[@murphyriddle5005]

But I still don't understand

[@kalelm2943]

The cardiac cycle refers to the sequence of events that occur and repeat with every heart beat. It can be divided into 2 major phases, Systole and Diastole. Each of which subdivides into several smaller phases. Systole and diastole refer to ventricular contraction and relaxation respectively. Reminders: - blood flows from higher to lower pressure - contraction increases the pressure within the chamber while relaxation lowers the pressure - Av valves open when atrial pressure are hogher than ventricular pressure and close when the pressure gradient is reversed - Similarly semilunar valves open when ventricular presures are higher than aortic pulmonary pressures and close when the reverse is true. Phase 1 atrial depo/contraction Phase 2 iso. Contrction Phase 3 rapid ejection Phase 4 reduced ejection Phase 5 iso. Relaxation Phase 6 ventricular filling The cycle is initiated when the firing of the SA node that stimulates the atria to depolarize. This is represented by the P wave in the ECG. Atrial contraction starts shortly after the P wave begins and causes the pressure within the atria to increase forcing blood into the ventricles. Atrial contraction however only accounts for a fraction of ventricular filling because at this point the ventricles are already almost full due to passive blood flow down the ventricles thru the open av valves. As atrial contraction completes, atrial pressure begins to fall reversing the pressure gradient across the av valves causing them to close. The closing if the av valves produces the first heart sound S1 and marks the beginning of systole. At this point, ventricular depolarization represented by rhe QRS complex is halfway thru and the ventricles contract rapidly building up pressures inside the ventricles. For a moment however the semilunar valves remain closed and the ventricles contract within a closed space. This phase is refered to ISOVOLUMETRIC CONTRACTION because no blood is ejected and ventriclular volume is unchanged. Ventricular EJECTION starts when ventricular pressure exceed the pressure within the aorta and pulmonary artery. The aortic and pulmonic valves open and blood is ejected out of the ventricles. This is the RAPID EJECTION PHASE. As ventricular REPOLARIZATION reflected by the T wave begins, ventricular pressure starts to fall and the force of ejection is reduced. When ventricular pressure drop below aortic and pulmonary pressures, the semilunar valves closed marking the ends of systole and beginning of diastole. Closure of semilunar valves produces the second heart sound S2. The first part of diastole is again isovolumetric relaxation as the ventricles relax with all the valves closed, ventricular pressure drops rapidly but their volumes remains unchanged. Meanwhile the atrium being filled with blood atrial pressure rise slowly, ventricular filling starts when ventricular pressure drops below atrial pressures causing av valves to open allowing blood to flow down the ventricles passively. The atrial contract to finish the filling phase and the cycle repeats itself.

[@mrk.8448]

thank you

[@taibaliaqat9560]

THANK YOU FOR THIS!

[@zixianooi7321]

thanks for thisssssss!!!!!!!!!!!

[@khasifpratama2303]

THANK YOU SM!!!

[@vanessaalbacite4599]

Really appreciated this summary

[@zmmnsaleh]

one second takes months to understand

[@gianluca0castell]

u got to think multilayer ,as of the electric chimical and mechanical events,then moving on a time lime everything becomes clearer

[@multikimberification]

poetic way to look at. Likey.

[@armin2621]

takes months to understand, yet you have to do it in one week XP

[@ujjwalprakash3170]

0.8 sec more accurately😛

[@pigeonlove]

the 480,000 views were just the 6k thumbs up folk watching 80,000 times on repeat

[@EvsPersonal]

This video just compiled an entire 100+ slides, 6 individual 10+ min videos, into a 5min animation. ANIMATIONS ARE SO UNDERRATED. you need to see the animation paired up next to a graph in order to grasp and apply the full concept of the Cardiac cycle. I've been looking for a video like this.

[@ilaydamahmutoglu5942]

same here 👍

[@beatricecajetan2632]

ABSOLUTELY! AS AN AUDIO-VISUAL LEARNER, THIS IS DEFS AN EXTREMELY HELPFUL TECHNIQUE

[@nneoma830]

Where are the animations?

[@moformedicine1260]

As a medical student, this took me a while to understand. But after practice and time and time of coming back to this video I would have to say this is the BEST video out there on the cardiac cycle, EKG, systole, diastole etc. It's 100% spot on.

[@shaun_rambaran]

Amazing! I never realised the sound of the heartbeat was actually the slamming shut of the valves. I always had assumed that somehow the muscle contractions made the sound directly.

[@filmonhaile3327]

Me too man 🤣

[@isabela6967]

THIS IS SUCH A LIFE SAVER. THANK YOU. alot of the videos dumb down the explanations and dont give you how they relate to the ecg recordings

[@rarazxra]

love it.

[@ericlewis6404]

If you're searching for videos that explain the CARDIAC CYCLE - STOP! LOOK NO FURTHER! This is THE BEST VIDEO on KZbin. Thank you!!!!!

[@SatieSatie]

When a 4 min video in a foreign language (foreign because I'm studying this in German) explains it a 100 times better than expensive text books over an entire chapter...

[@hibaomair3160]

Lol, honestly, KZbin teaches better then books, sometimes, plus, its cost free.

[@germoney9998]

An welcher Uni bist du

[@C_Castillo]

For real tho lol

[@abdallahhariri6798]

a non-understandable 90 mins lecture reduced into an amazing 4 mins video!!! god bless you, you help medical students around the whole world

[@khalidkingkhankhan6782]

Abdallah Hariri are you a medical student ? of which university

[@abdallahhariri6798]

@@khalidkingkhankhan6782 Yes I'm, Misr University For Sience And Technology (Egypt)

[@en_lune]

you literally changed my life in just 4 minutes i cannot thank you enough

[@iceychaos1234]

This is incredible. Easily the shortest yet most comprehensive overview of the cardiac cycle I have found yet. Textbooks make it seem more convoluted than it actually is.

[@deborahr113]

This is probably one of the best, most informative videos on human anatomy I have ever watched.

[@daniellarios9139]

For the past couple weeks I couldn't get anyone to successfully explaine systole and diastole.. within the first 20 seconds of this video I finally feel confident about the entire process! Thanks for filling in the gaps and sharing this. Great video!

[@udprakash]

I, as a physiologist, found these medical education videos from Alila Medical Media very simple, informative and well explained in almost every clinical perspective.

[@rugvedpawar7114]

Thank you Mr. Prakash

[@halliereeve3961]

Clearer than the two hours worth of lecture videos I had to watch to get this information! Thank you!

[@rosybala2223]

Best video ever. Kudos to creators. You saved millions of med students. Thank you.

[@doodoobearlove]

amazingly putting all the chart together at same time comparing with the heart on the side that really helps us to have a more complete pic of what's really going on at diff stages.

[@thajasnethomas778]

Thank you so much... this has made my fundamentals very strong. Once again, really appreciated!

[@kamranyahyaabadi9399]

This video is presented awesomely thank u , though lets remember that there is also a " Dicrotic Notch " seen in the aortic pressure right in there while the pressure in the ventricles is falling as they relax , and this notch is there because once the aortic valve closes ( to prevent backflow ) some of this blood that wants to flow back into the ventricles from the aorta , bumps into the closed aortic valve and bounces back .

[@sherinhsb]

Thank you for explaining it step by step. It's really helpful. I saw this diagram on books but haven't got any information out of it. But now I can see how useful this diagram is.

[@jourdanhamme4065]

This is incredible Thank you You just simplified the Wiggers Diagram

[@dimplegupta864]

Amazing..!! Excellently explained in shortest time possible Thanx😊

[@babynewms]

THANK YOU!! months of half-understanding fixed in under 5 minutes.

[@vineetaggarwal9316]

One of the best videos I have came across

[@oL4Sinfulo]

This Cardiology playlist is awesome! Thank you

[@afifanaeem4425]

The way presentation the so inspiring and understandable...made basics strong...and unlike other videos proper events in a cyclic way are explained...it's no less than a life saver

[@thanurirajapakshe3455]

Thank you so much, A clear explaination. 4 minutes video for 1 hour lesson taught me perfectly

[@viennajune2267]

I'm 14, taking gifted bio classes. this helped me a lot because I didn't understand anything in class. very clearly explained

[@iceasneeded]

Thank you! Seeing ALL of this at the same time helped me SO much!

[@christycrysalide3656]

Thank you SO MUCH ! I have my final exams soon and i had troubles to understand this part so THIS IS AMAZING ! THANKS ! 😍

[@tharubaskaran]

Give this channel a award just for this video!✨

[@quotesandthoughts666]

This video deserves 10M views! 💓 Precise! On spot! Perfect!

[@anna_aka_epicinternetgf]

Excellently explained! And the visuals are so easy to follow! Great job

[@magdalenobrayan]

i just spent like 5 hours figuring this out when i could've just watched this video, fml in addition i kept getting confused when i would see AV valve(s) and think they were referring to the aortic semilunar valve and was about to cry

[@bitaswift6537]

That was awesome! I really appreciate what you do because it really helps me to understand

[@devanshitalati134]

Omg thank you so much Perfectly explained in just 4 minutes

[@kennystallcup435]

I remember watching thia video in the past years just to know the phases of the heart cycle. i returned once again to see how its denoted on the EKG. just to say its lovely how so much information and diversity is given in 1 Video

[@doricevalery7416]

Thank you for summarizing a 6 hour lecture ❤❤

[@xuhan3781]

This is wonderful!!! Thank you for all your great videos!!!

[@robertabristotsilvestrin3601]

Thank you so much for helping me teach human physiology to my students!

[@serendipity_6179]

Thank you so much. This helped me more than any lecture or textbook

[@hg8301]

wow how wonderfully explaind! i really appreciate this video!

[@madarchod312]

amazing. 15 pages of knowledge in 4:10 minutes. THANKS.

[@birch3607]

This was so beautifully explained! Thank you!

[@nicholeknight1893]

Thank you, I'm taking pathophysiology and needed a refresher ♥️

[@dr.fakhar-ul-islam2297]

Fantastic approach. Highly appreciable.

[@glengeorge5888]

That graph is the bane of my existence

[@119alias]

Best channel for medical videos ! Please keep going!

[@shreyasinha3279]

This vedio was worth watching.....I mean....entire thing in just 4 mins......That's what we need!!Loved it!

[@raeesahfirdhouse5902]

excellent. this video completed the puzzle which was scattered in my brain

[@vaibhavjain3234]

This channel is GOLD!!

[@Olivia-tb9kk]

This is soooooo helpful before exams tomorrow, thank you!

[@anshumehta8222]

Best video to understand cardiac cycle with all details and important points Thanks a lot

[@Dr.Kamran97]

liked subscribed and shared this video because this is the least i can do to show my gratitude. thank you for saving the day of us all.

[@erzas556]

I don’t know how to thank you, very well explanation with the heart picture and animation of the cycle with the ECG diagram! Thank you sooooo much

[@surendrakumarsingh8760]

Thank you. Now its easier to understand this concept.

[@hangman2869]

really good video, very condensed but otherwise accurate and easy to understand

[@tasneemfahoum5931]

great simplified explanation. Thank you!!

[@mckenzilewis7554]

These videos are absolutely AMAZING

[@YouCanDoX]

WOW amazing video. You saved me from going crazy on cardiac physiology

[@mickeyromero9233]

Thank you for your KZbin services

[@MrTumeketeke]

one of the best videos to learn from...thank you

[@NouraFares_]

Excellent explanation. Thank you

[@scott8908]

Currently a Paramedic going through ADN school to become an RN. Cardiology is a weak point for me but this video helps a ton. Thanks

[@luqmanahmed3191]

Wow 🤩you guys are doing so cool ✨ the animation and the explanation is so unique and makes the lesson so much simple thanks 🤗

[@fionanaluwende4173]

Thank you, it was helpful, simple to understand

[@anasqureshi6036]

this is too good make videos on working of ear eye and kidney also

[@beingbaby3741]

thnk u, i've a presentation about tht and this helped me sm

[@entertainmentzone9549]

Hello, I have a presentation about this topic, can you help me by sending some documents that you made previously for your presentation... Plz. 🙏🙏🙏🙏

[@justanotherhuman5162]

All I can say is God bless you ma'am!. Thank you

[@putuyudhistiraokawardhana9614]

Thank you so much for this content. It's easy to understand.

[@abdulazizusman2725]

Really wonderful video. I watched many videos about cardiac cycle but not one was able to illustrate it in a comprehensive way like this video. You've earned my subscription and like 👍

[@Dr.Aishwaryajoy717]

Thank u explaining the complex process in a simple way

[@Alilamedicalmedia]

Happy to help

[@rajeevmahajan9227]

Simply awesome...not from medicine background but never realized while I was watching the video

[@kyleFed]

This video is very helpful! Thank you so much!

[@smtdrgeetachavan6125]

Beautiful. u made very easy to understand the cardiac cycle.

[@aleenahmohsin1060]

Probably the best explanation of cardiac cycle on internet so faar!

[@ghassanauf8103]

your videos are the best and are better than thousand lectures

[@lkw5699]

Articulate and explained slowly. Excellent graphics

[@Josey168]

This was so incredibly helpful!

[@jaycilangehennig2059]

Thank you! From a Music Ed major that has to take Life Science to graduate. Science is like learning French for me 😩 but this really helped! 😃❤

[@user-pp4kp2wy1h]

Hallo

[@yashvantbudania_1008]

Best video on cardiac cycle ever by a distance

[@aboodyghost2155]

Every second is important in this video!

[@shahad7952]

For real guys THANK YOU SO FREAKIN MUCH

[@janeallen9736]

THIS WAS VERY HELPFUL!!! thankyou so much. Bless You

[@deepakrawat_28vcsg78]

Regulation of bp.. short and long term.... Thank you so much .. great job guys

[@farroqbhatti4450]

Wonder me 💓 so easy and simply explained . Love 💖 it.

[@rayhanah_hussain]

Woooowwww,best explain in world's about the "Cardiac cycle"😍😌😔... Greetings from a medical student in Iraq🇮🇶😍💪🏽

[@madelinpozadas7454]

This video was so helpful! Thank you so much!

[@ruchidesai7448]

Very helpful...can you plz make video for pyramidal track?

[@haifaaferas8311]

I'm watching this for my A levels and I wish anyone told us about it before.. Amazing video

[@roberttucker1527]

One if the finest videos on the subject

[@dineshmanoj6527]

Man that’s the best one out there thank you for such a great video

[@ayaelraggal9323]

Just more than perfect !!

[@debbietidwell2482]

EXCELLENT video‼️ Thank you‼️

[@alonator09]

THANK YOU sincerely, stressed out dental student :')

[@abhinavadvani3996]

Me too By the why which country u are from

[@abdulazizaljohani4611]

Same here sis ):

[@panicpalette]

Alexandria Talley same.

[@muhammadosamaelsayedbaioum6110]

Same here guys :")

[@mashagrey]

saaaame :D

[@rahulposa]

waaahhhhh ive never seen like this type of video and simple explanation thq fr the video qnd explaining

[@maahi8218]

Thank you 😊 your way of explanation is excellent 😍

[@RouRoro]

I love this graph!

[@laraibnadeem125]

I was stuck in this topic for an hour and you taught me that in minutes..... thank you so much...!!!