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How does the blood move around the body? What is the role of the heart in bringing blood to all the different parts of the body?
Watch and see as Leslie gives an overview of the Circulatory System, the first in this series.
Enjoy!
Transcript of Today’s Episode
Hello and welcome to another episode of Interactive Biology TV where we’re making Biology fun! My name is Leslie Samuel and in this episode, Episode 44, I am going to be talking about how blood flows through the heart. This is going to be the first video in the Circulatory System series. So, let’s get right into it.
Here, we are looking at two pictures of the heart. On your left, we’re looking at the heart when it’s being filled with blood. On the right, we’re looking at the heart when it’s pumping the blood out of the heart. We’re going to look at a number of details here just to give an overview of how the blood flows through the heart. In order to understand how the blood flows through the heart, we need to look at the valves that are found in the different parts of the heart.
First of all, allow me to point out that this is the right side of the heart so, this is right. Over here, we have the left side of the heart. Now, that looks a little strange because when you’re looking at the screen, this is your left and this is your right. But, this is looking at it as an individual that’s facing you. This would be his right side and this would be the left side.
There are a number of valves that are found throughout the heart. There are a number of parts of the heart that we need to know.
The first thing I want to point out is here, we have the right atrium and the left atrium. So, this chamber is the left atrium. This chamber is the right atrium. Then, we have the right ventricle and the left ventricle. Same thing over here, we have the right ventricle, left ventricle; right atrium and left atrium.
The next thing I want to point out is that between the atria and the ventricles, we have what we call the atrioventricular valve. And that makes sense since it’s between the atria and the ventricle. So, here we have an atrioventricular valve, here we have an atrioventricular valve. Now, on the right side, we also call this atrioventricular valve a tricuspid valve. We call it “tricuspid” because it has three cusps, in other words, three flaps. You’re only seeing two here but, that’s because this is a cross-section. Then, on the left side, we have what we call the left atrioventricular valve which is also known as the mitral valve or the bicuspid valve. I’m just giving you these different names so that if you go and read a textbook and it says one of these, you know exactly what it’s talking about. So, we have the tricuspid or the right atrioventricular valve and the bicuspid or the mitral or the left atrioventricular valve.
Then, we have valves that allow blood to leave the ventricles. On the right side, we have the right semilunar valve and that is also called the pulmonary valve. The reason it’s called a pulmonary valve is because it leads into the pulmonary artery. On the left, we have this semilunar valve which we can also call the aortic valve. We call it the aortic valve because it leads into the aorta.
So, these are the different names and I want you to know these names: tricuspid, bicuspid, mitral, atrioventricular, aortic, semilunar, which is the pulmonary and the aortic. Those are the valves that I want you to be familiar with.
The special thing about valves is that it allows for blood to flow in one direction. So, here you can see blood can flow into the ventricle but, it can’t flow back. If it tries to flow back, these valves are going to shut. So, all of these valves are one-way valves. They allow for blood to flow in one direction.
Now that we know the different valves, let’s look at how blood flow happens. Blood comes back from the body and it enters into the heart via the vena cava. So, you can see blood is flowing into the vena cava. We have the posterior vena cava and we have the anterior vena cava. Blood is coming in, entering into the right atrium.
As it enters into the right atrium, the atrium contracts and that pushes the blood into the right ventricle. Once the blood gets into the right ventricle, the ventricle contracts and that pushes the blood through the semilunar valve or the pulmonary valve into the pulmonary artery. And from here, that blood goes to the lungs. And, it goes also in this direction to the lungs.
Once the blood goes to the lungs, it picks up, you guessed it, oxygen because you’re breathing in the oxygen. That oxygen aids the blood. Once the blood gets oxygen aided, it leaves the lungs and goes via the pulmonary veins into the left atrium. The left atrium contracts sending the blood through the left atrioventricular valve into the left ventricle. Once the blood is in the left ventricle, the left ventricle contracts and that sends the blood through the semilunar valve or the aortic valve in this case, into the aorta, and then, that blood can go to the rest of the body.
I know this looks a little confusing with all of these arrows but, let’s follow that one more time. Blood comes from the body. It enters via the posterior and anterior vena cava into the right atrium. The right atrium contracts and that pushes the blood through the tricuspid valve or the right atrioventricular valve into the ventricle. The ventricle contracts and that pushes the blood via the semilunar valve or the pulmonary valve to the pulmonary arteries that go to the lungs, picks up oxygen, then it comes back oxygenated via the pulmonary veins into the left atrium. The left atrium contracts and that pushes the blood into the left ventricle. The ventricle contracts, pushing the blood via the aortic valve or the semilunar valve to the aorta and out to the rest of the body.
So, the function of the heart is basically to pump the blood to the body, to send the blood to the lungs to pick up oxygen, and then to send that oxygenated blood to the muscles and to the organs that need it. Once the muscles and the organs that need it, once they use that oxygen, the blood comes back via the vena cava to the heart. The process can continue over and over again.
I have these two over here and you can see, this shows the heart filling with blood and, this shows when the ventricles actually contract and send the blood out to the lungs and to the rest of the body via the aorta.
There’s one thing I’d like to emphasize though. I say that, first the right atrium contracts and then the right ventricle contracts, and I’m saying that just because I’m showing it one at a time. But, both atria contracts simultaneously and both ventricles contract simultaneously. So, that while this process is happening, this process is also happening. Blood is being pumped to the lungs. At the same time, it’s being pumped to the rest of the body.
That gives you a general introduction into the circulatory system by showing you how the heart pumps blood.
As usual, you can visit the website at Interactive-Biology.com for more Biology videos and other resources. That’s all for this video, my name is Leslie Samuel and I’ll see you on the next one.
About The Author Leslie Samuel
Leslie Samuel is the creator of Interactive Biology. He created this site to help Make Biology Fun and has the goal of making this the biggest and best biology resource on the net.
8. May 2011 at 3:28 pm
Great site! Thank you!
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Lrsamuel Reply:
May 9th, 2011 at 1:28 pm
You are very much welcome Lisa
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16. May 2011 at 12:23 pm
Thanks Leslie for your videos. There are very good teaching material. I am a doctor from Sri Lanka. I am responding to the question on terminology raised by Livinglifehigh as to whether it is correct to call them posterior and anterior vena cava or Inferior and superior vena cava.
In man, they are called Inferior and superior vena cava as man is biped and when standing upright it is inferior and superior in its orientation to the heart.
However, I can imagine you being a biologist and all animals are mainly quadruped the ‘superior vena cava’ becomes ‘anterior vena cava’ and ‘Inferior vena cava’ becomes ‘posterior vena cava’. This is my guess why you call it so. So I think both terminologies are acceptable.
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Lrsamuel Reply:
May 16th, 2011 at 3:47 pm
Heyy, thank you so much for your input. I really appreciate it. The more people chime in, the better!
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12. September 2011 at 9:30 am
There seems to be a problem downloading the video for 044 How Blood Flows Through the Heart, it says I need a password, other videos have downloaded Ok – Great site though
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Lrsamuel Reply:
September 12th, 2011 at 12:08 pm
Thanks for pointing that out. I’ve fixed the download link.
All the best!
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9. November 2011 at 12:27 pm
@shawnagh You’re very much welcome. We’re happy to know that we were able to clarify things for you. Stay tuned, because we have more videos coming!
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16. November 2011 at 10:54 pm
I am so glad I found this video. We are studying Cardiovascular system in A & P now and I just could not grasp the flow, but now I totally understand.
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17. November 2011 at 6:16 am
@shanaspeck Leslie explains them as simply as he can for everyone to understand. You can visit our website for more cardiovascular system videos. I’m sure you’ll find value in each of them. Thank you for watching and stay tuned for more!
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20. November 2011 at 10:02 pm
This video saved me! I have. Test on this tomorrow and I didn’t understand the way the book made it out. After watching this I get it a lot better!! Thank you soooo much!
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21. November 2011 at 7:12 am
@ChibiNyaaX3 Glad you’re finding value in our videos. Thank you for watching! Please stay tuned for more Biology videos coming soon!
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23. November 2011 at 8:47 pm
In The name of God
Hello
Thanks for your video
very useful for more education
but i have wrong in this video
in picture worte anterior and posterior vena cava but it’s wrong
there are superior and inferior vena cava
Thanks for your video
Islam is my way until beyond
God’s my trust
God keep’s me
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23. November 2011 at 8:48 pm
In The name of God
Hello
Thanks for your video
very useful for more education
but it’s wrong in this video
in picture worte anterior and posterior vena cava but it’s wrong
there are superior and inferior vena cava
Thanks for your video
Islam is my way until beyond
God’s my trust
God keep’s me
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23. November 2011 at 9:30 pm
@issayk1 Hi! Thank you for watching. Yes, we had the discussion on the error below in the earlier comments posted. You can go ahead and check them out.
Please stay tuned for more Biology videos
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24. November 2011 at 2:13 pm
Hello, one quick observation… 4::54…. Posterior and Anterior vena cava.
(superior – inferior)
I think it’s Superior (Anterior) and Inferior (Posterior). I’m from Romania… and we studied them like that…. and I’ve seen pretty much videos (USA made) which say the same thing
Anterior = in front of. Posterior = behind.
They have the same position, only one collects no oxigen blood from superior members + head, and the other one from the down below body.
Keep up the good work
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24. November 2011 at 4:22 pm
@XSymphony Yes, this error was already discussed. Please refer to the previous comments below. Thank you!
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24. November 2011 at 5:24 pm
@InteractiveBiology sorry, my bad, didn’t checked all comments.
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25. November 2011 at 2:09 am
@XSymphony Not a problem
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30. November 2011 at 9:44 pm
i have i science test on this tomorrow, this helped a lot
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30. November 2011 at 9:44 pm
i have i science test on this tomorrow, this helped a lot
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1. December 2011 at 5:35 am
@FLUFFYburito Great! Hope you ace your test. Good luck!
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1. December 2011 at 1:27 pm
I have an anatomy test on Monday and this helped me – it was easy to follow and a clear demonstration! Thanks for posting.
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1. December 2011 at 1:28 pm
@issayk – they can be reffered to as anterior/superior/cranial and posterior/inferior/caudal, interchangeably. They are all correct…
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1. December 2011 at 7:24 pm
@sylverteaz You’re welcome! Glad to know this helped. Stay tuned for more Biology videos
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5. December 2011 at 11:54 am
great vid thanks alot really heped me with my biology exam thumbs up
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5. December 2011 at 9:36 pm
it really helps. Great Video..!
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6. December 2011 at 9:55 am
@raiamirr Thank you!
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6. December 2011 at 9:56 am
@lemonmasherboi That’s great! Stay tuned, we have more Biology videos coming very soon!
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7. December 2011 at 2:27 am
Thank you for posting Leslie. You are truly an inspiration.
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8. December 2011 at 9:37 am
@norcoboy Leslie’s inspiration are actually his viewers. You are his reason why he wants to keep on doing what he’s doing at his Biology website. Stay tuned. He has more videos coming very soon!
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10. December 2011 at 9:00 pm
thanks alooooot u r amazing
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11. December 2011 at 1:19 am
@CamelliaASultan You’re welcome! Please stay tuned. We have more Biology videos coming soon!
Have fun learning Biology!
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18. December 2011 at 5:25 pm
LOVE THIS CHANNEL
SO HELPFULL
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18. December 2011 at 5:36 pm
@sheilayoyo Thank you! We’re glad to be of help. Please stay tuned as Leslie will be making more Biology videos for the site. Thank you!
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21. December 2011 at 12:46 pm
if you can , please may you make a video on plants as in plant transport system , (xylem and phloem)…
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21. December 2011 at 1:52 pm
@Dipsy260495 Hi, unfortunately, Leslie is no longer taking requests for specific videos. He’s loaded with a lot of work that it would already be impossible for him to do all requests. But, nevertheless, we hope you’ll still find the site helpful. Good luck with your studies!
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23. December 2011 at 1:03 am
O my, very interesting. Thx Leslie you made it very easy to understand. Keep up the good job. Thumbs up
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23. December 2011 at 12:21 pm
@adamski03able Glad to know you found value in them. Please stay tuned! We have more Biology videos coming soon!
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27. December 2011 at 6:01 pm
hello leslie could you make explaination on smooth muscle’s contraction mechanism please?
i dont understand about the calmadulin-calcium complex,myosin light chain kinase,myosin light chain phosphatase and the latch bridge.thanks a lot anyway.
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2. January 2012 at 1:31 am
tx for the upload, keep up the good work, knowledge for all!
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5. January 2012 at 8:37 am
Is this guy from reading rainbow?
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17. January 2012 at 5:27 pm
Good video. Easier to follow than most
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18. January 2012 at 11:26 am
Thank you for explaining this in a fun and easy way
cheers mate
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18. January 2012 at 11:26 am
Thank you for explaining this in a fun and easy way
cheers mate
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24. January 2012 at 9:37 am
Great video, you did a great job!
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1. February 2012 at 8:05 pm
i wish you were my teacher!
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5. February 2012 at 1:24 am
This is so awsome i actually understood everything thank you!! Great video 2 thumbs up!
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5. February 2012 at 12:12 pm
id like to know how when the papillary muscles contract which also makes the chordae tendinae pull back and taking notice that the tricuspid valve is connected to the chordae tendinae do the valves open or do they close when the papillary muscles contract along with the chordae tendinae and during when the atria contracts.
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5. February 2012 at 12:12 pm
id like to know how when the papillary muscles contract which also makes the chordae tendinae pull back and taking notice that the tricuspid valve is connected to the chordae tendinae do the valves open or do they close when the papillary muscles contract along with the chordae tendinae and during when the atria contracts.
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5. February 2012 at 12:15 pm
oh and you might have to correct the decription of the vena cava its superior and inferior not anterior and posterior. But it was a great video for clearing my understanding of blood circulation but im confused what relationship do the papillary muscles have when the atria is contracting or not and how it affects the valves.
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6. February 2012 at 6:32 pm
So incredibly helpful, you are such a blessing!!
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6. February 2012 at 10:36 pm
I loveeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee this guy he makes all this topics very simple !!!!!!!!thank you for you help
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14. February 2012 at 12:14 pm
I wish you could get my tuition instead of my physio prof…
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