What's going on everybody? This is Medicosis Perfectionatus, where medicine makes perfect sense. Let's carry on our biology playlist.
In the last videos, we finished the respiratory system. Today, we'll talk about the cardiovascular system in an introduction. This is for biology students. For the pros, stay tuned for an upcoming series called Cardiology. This is my biology playlist.
Try to watch these videos in order. You have to be able to repeat verbatim everything I'm going to say in this slide. Let's start here in your left ventricle.
Left ventricle is going to pump blood to the aorta through the aortic valve. Blood is in the aorta. Blood is going to go all over your body in the systemic circulation. Until you give each cell oxygen, the cell is going to use that oxygen in metabolism.
As you know, metabolism produces carbon dioxide. This carbon dioxide will be dumped onto veins in the systemic circulation, until you end up here, in the inferior vena cava, and here, the superior vena cava, from the lower half of the body and the upper half of the body, respectively. Regardless, you will end here, in the right atrium, which contains deoxygenated blood, which means blood that has carbon dioxide and less oxygen.
We are here in the right atrium. Right atrium is going to push blood to the right ventricle through the tricuspid valve. Deoxygenated blood is here in the right ventricle. Right ventricle is going to pump this deoxygenated blood into the pulmonary trunk.
And then right pulmonary artery, left pulmonary artery will carry the deoxygenated blood to the lungs. The lungs will take that carbon dioxide, breathe it out, and breathe oxygen in. This lovely oxygen is going to go to the blood and end up here in the pulmonary veins.
Two from the right lung, two from the left lung. Eventually, they end up in the left atrium. Now, the left atrium contains oxygenated blood.
Left atrium is going to pump that oxygenated blood to the left ventricle through the mitral valve. So, we have four chambers in the heart. Left atrium, left ventricle.
Right ventricle. Right atrium, right ventricle. We have four valves in the heart.
Mitral valve between left atrium and left ventricle. Aortic valve between left ventricle and aorta. Tricuspid valve between right atrium and right ventricle.
Pulmonic valve between right ventricle and pulmonary artery. Please pause the video and try to tell the story to yourself. Let's do it again.
Oxygenated blood leaves the left ventricle through the aortic valve. into the aorta. The aorta will take that oxygenated blood all over your body.
Give oxygen to the cell, take carbon dioxide from the cell. Deoxygenated blood is going to go to the inferior vena cava and superior vena cava, ending up in the right atrium. Right atrium will give the deoxygenated blood to the right ventricle through the tricuspid valve, a valve with three cusps.
Right ventricle is going to pump the deoxygenated blood to the pulmonary trunk through the pulmonic valve. which also has three cusps. Pulmonary trunk, pulmonary arteries, lungs. The lungs will get rid of the carbon dioxide and provide you with oxygen.
Oxygenated blood is going to end up here in the pulmonary veins into the left atrium. Left atrium will give the oxygenated blood to the left ventricle via the mitral valve. Why do you call it the mitral valve? Because this is the mitral. What's the mitral?
This is the bishop's hat, which as you see here has like two cusps. Mitral valve also has two cusps. That's why they called it mitral. Mitral valve is the only valve with two cusps. Everything else has three cusps or three leaflets.
All of this was the adult circulation. But how about the fetal circulation? We talked about this in a separate video in this biology playlist. It was epic.
The left side of the heart contains... oxygenated blood. The right side of the heart contains deoxygenated blood. And of course, you remember that in adults, the lungs are functional.
But in a fetus, the lungs are not working. But where does the fetus get the oxygen from? From his mother's placenta, doofus.
Valves. The heart has valves. Vessels have valves. I'm talking about veins. How about arteries?
They don't have valves. How about capillaries? They don't have valves. Only veins do. The heart has four valves.
Mitral valve, triguspid valve, aortic valve, and pulmonic valve. All of them have three cusps. Except the mitral valve, which only has two cusps. Remember the hat of the bishop, the mitre. La mitre.
My French is on fleek. The mitral valve is between the left atrium and the left ventricle. Here. Tricuspid valve is between right atrium and right ventricle.
Here. These are atrioventricular valves. Between the atrium and the ventricle. Between the atrium and the ventricle.
Love it. Their anatomical location is here. Above them is the aortic and pulmonic valve. We call these semilunar valves. Some people call them AP valves.
AP or aortic, P is for pulmonic. Mitral and tricuspid lie below aortic and pulmonic. Four chambers, four valves, and four pulmonic veins. You know that arteries are supposed to carry oxygenated blood, right? The pulmonic artery is an exception.
It's an artery. but it carries deoxygenated blood. You also know that veins are supposed to carry deoxygenated blood, except those pulmonary veins. They are veins, but they do carry oxygenated blood.
Some people are so naive to the point of believing that an artery has to carry oxygenated blood. No, that's not the definition of an artery. An artery is a vessel that takes blood from the heart to another organ. In other words, away from the heart.
and towards the organ. A vein is the exact opposite. It's a vessel that takes blood from an organ to the heart, towards the heart, away from the organ. That's the definition. And this is true whether you're talking about an adult or an embryo.
In adults, arteries carry oxygenated blood except pulmonary artery. But in an embryo, the artery carries deoxygenated blood as we have discussed before. Example here is the umbilical artery.
It's a branch of the internal iliac artery of the embryo. Takes that deoxygenated blood and gives it to mommy's placenta. In adults, veins carry deoxygenated blood except pulmonary veins. But in embryo, veins are vessels that carry deoxygenated blood fresh from mommy's placenta towards the baby's heart. Love it.
If my channel helped you this year, please consider buying me a coffee. Go to buymeacoffee.com slash medicosis. Left ventricle pumps oxygenate blood to the aorta. Here is the ascending aorta, here is the aortic arch, and here is the descending aorta. In the chest or the thorax, it's called the descending thoracic aorta.
After it descends below the diaphragm, we call it the abdominal aorta. abdominal aorta carries oxygenated blood from the heart towards other organs. But the inferior vena cava, which is next to the aorta, carries deoxygenated blood from organs to the heart. Of course, these organs are in the lower half of the body.
Notice the difference between the thickness of the wall of these vessels. Arteries have stronger walls, thicker walls. They can withstand higher blood pressure.
Veins, on the other hand, have weaker walls, lower pressure, and therefore more easily compressed. We will talk about this point in great detail in an upcoming video titled The Vasculature. Another concept to understand is preload versus afterload.
Pre means before, after is after. Before the heart, we're talking about the venous return, which is the blood coming back to the heart. After load is the resistance that the heart is going to face after it pumps. So after I pump, oops, I have resistance here in the vessels. Imagine that someone is running behind you and then you hit a wall.
The person who is behind you is the preload. The wall that is after you is the afterload. The heart has to live with both.
Skeletal muscles versus cardiac muscles versus smooth muscles was a topic of a separate video. And you can search YouTube for skeletal muscles versus cardiac muscles versus smooth muscles, and you will see my videos. Cardiac muscles are striated, branching, involuntary, uninucleated, automatic.
You cannot say to your heart, hey, pump faster or slower. You just can't. The heart can initiate its own nerve impulses. It does not need outside forces. The sinoatrial node of the heart has automaticity.
Cardiac muscles have troponin, they have gap junction, also known as nexus. Now we will use this slide to review the fetal circulation. Please do not review this before you watch my fetal circulation video first.
Let's go. Later circulation. Here is the placenta. The placenta is providing the baby with pure oxygenated blood. Oxygenated blood is gonna go here.
We're talking about umbilical vein, which is going to the heart. What's the definition of a vein? A vessel that takes blood from an organ to the heart.
Thank you. And this is carrying oxygenated blood. We're talking about the fetus here. Here is a vein that is carrying oxygenated blood. This oxygenated blood is going to go up and we're going to bypass the liver.
How do you bypass the liver? Through the ductus venosus. And then we are here in the inferior vena cava. We will go to the right atrium.
Between the right atrium and the left atrium, there is a foramen known as the foramen ovale. Here is the foramen. Blood is gonna go from the right atrium to the left atrium through the foramen ovale, which is open in the fetus, but it's not open in adults.
Blood will go from left atrium to the left ventricle, from left ventricle to the aorta, from aorta throughout your body, this is the systemic circulation, back through inferior and superior vena cava to the right atrium. Blood is coming here from the upper part of the body, right? This is deoxygenated blood. It's going to go from here to the right ventricle, pulmonary trunk, pulmonary arteries, and there is ductus arteriosus, which is a duct between two arteries, that's why it's called arteriosus.
It's between the left pulmonary artery and the aorta. And this is carrying deoxygenated blood from the left pulmonary artery to the aorta. Why are we doing this?
Because we are bypassing the lungs. Why are we bypassing the lungs? Because this is a fetus.
The lungs are not functioning yet. Deoxygenated blood will leave the left pulmonary artery, goes to the aorta, and this deoxygenated blood will end up in something called umbilical artery, which carries deoxygenated blood towards mommy placenta. Mommy's placenta is gonna get rid of the carbon dioxide, give us pure, lovely oxygenated blood, back to the umbilical vein, and you repeat the cycle. For more lovely animations like this, go to picmonic.com slash VIP hookup slash metacosis.
These are not just still pictures, these are animated videos as well. Question of the day. Regarding the adult circulation, not fetal, we're talking adults here.
Choose the correct answer among these. We're talking about portal vein, hepatic vein, hepatic artery, pulmonary artery, pulmonic vein. which one is oxygenated, deoxygenated, etc.
For example, if you chose A, you agree that the portal vein is deoxygenated, hepatic is deoxygenated, hepatic artery is oxygenated, pulmonary artery is deoxygenated, pulmonary vein is deoxygenated. You know, it goes this way, it also goes this way. So, let me know the answer in the comment section, you'll find the correct answer in the next biology video. If you like this video, check out my cardiac pharmacology course on my website, I also have a kidney physiology course.
January is coming to an end and this discount is available for a very short period of time. Use New Year Learning to get a 60% discount quickly before it's gone. Go to medicosisperfectionitis.com.
Thank you for watching. Please subscribe, hit the bell, click on the join button. You can support me here or here. Go to my website to download my premium courses. Be safe, stay happy, study hard.
this is Mitokosis Perfectionitis where medicine makes perfect sense.