Heart and Blood Flow

Video Transcription

Welcome to this lesson today on heart structure and function.

Today we are going to be discussing the major structures of the heart and their role in the overall functioning of the heart.

The heart. First of all, we need to understand what the heart is, and what it does. The heart is a muscular pump whose job is to pump blood throughout the body. And it's a very complex organ made up of various different parts. We're going to look at a few of the most important parts of the heart today. Basically what we're going to be doing is just labeling this diagram here, and as I label the different parts, I'll explain what their purpose is.

Let's start right here with the left atrium. Our heart is broken up into two different halves. We have our right half and our last half. So this is our left atrium. So the other side here we have our right atrium. As I mentioned, our heart is broken up into two halves, and each of those halves is broken in half again. So our heart is actually composed of four chambers. The top chambers of our heart are referred to as the atria. So we have our left atrium in the left side of our heart, and our right atrium in the right side of our heart.

The two bottom halves are referred to as ventricles. So we have our left ventricle, and our right ventricle. Blood will flow into our atria, and then down into our ventricle, and then from our ventricle it will either be pumped to our body or to our lungs. So the atria are the top portions of the heart, and the ventricles are the bottom portions of our heart.

From there, we're going to define the septum. So the septum here, basically the septum, it's purpose is to separate the two halves of the heart. So you'll notice it separates the right half of the heart from the left half of the heart

The pericardium, located here, is the outer portion. The pericardium basically is a fluid filled sac that surrounds the heart, and its job is to protect and to lubricate the heart. So that's our pericardium.

Next we are going to label up here, we have our aorta. Our aorta is an artery that delivers blood to the body. It's part-- it delivers blood to the systemic circuit. So it's a large artery that aids in delivering blood throughout the body.

Our next part that we're going to label is our superior vena cave. Now our superior vena cava, its job is to deliver oxygen lacking blood from the upper portion of our body into the right atrium. So blood that needs to collect more oxygen-- all the oxygen has been used up-- enters through the vena cava and into the right atrium.

And then our inferior vena cava is located right here. So if our superior vena cava delivers oxygen lacking blood from the top part of our body, then our inferior vena cava delivers blood-- oxygen-lacking blood from the bottom portion of our body. And it's also going to deliver it up into the right atrium. So both the superior and the inferior vena cava deliver oxygen-lacking blood to the right atrium.

The next part that we're going to label is our pulmonary valve. Our pulmonary valve is located right here, as part of the end of the right ventricle. Our pulmonary valve allows blood to flow from our right ventricle to our pulmonary artery.

The next part is our aortic valve. Sorry, that's a little bit tough to read. It says aortic valve. Right here. So this is our aortic valve, and our aortic valve allows blood to flow from the left ventricle to the aorta. here

We're missing a couple valves. There we go This valve right here is called our left atrial ventricular valve. And then we have our right atrial ventricular valve here. And I'm just going to abbreviate it the AV valve. So we have an atrial ventricular valve on our right side, and our left side of the heart. And basically our AV valves allow blood to flow from the atrium to the ventricles. So blood, when it flows into the atrium, the atrial ventricular valve will then open, allowing that blood to flow down into the ventricle. And it also helps to prevent back flow. So we don't want blood that's in our ventricle to back flow into our atrium. So this valve is a one way valve. We have it on our right side and our left side. so it allows blood to flow from the right atrium into the ventricle, but at the same time preventing back flow.

Basically what happens when blood flows into our heart is that blood will enter into the right atrium. It will go through the AV valve into the right ventricle, up through the pulmonary valve. It will then be sent to your lungs to collect oxygen. So blood that enters this side of the heart is oxygen-lacking. It will then collect oxygen, enter into the right atrium, now that is oxygen-rich, into the I'm sorry, into the left atrium, and then into the left ventricle through the AV valve, up through the aortic valve, and then will be pumped throughout your body. And then your body will then use that oxygen, and then the blood is now oxygen-lacking again. And then we'll go through this process again, of going through the right atrium, right ventricle, up to the lungs, et cetera.

This lesson has been an overview on the major structures and the function of those structures of the heart.

Video Transcription

Welcome to this lesson today on the pulmonary and systemic circuits. In this lesson today, we will be examining blood as it flows through both of these circuits. So the pulmonary and systemic circuit are two circuits of blood flow. And in our heart, we have four different chambers. Our heart is divided into two halves, and each half is divided into two chambers.

So each half of our heart pumps blood in a different circuit. The right side of our heart pumps blood in the pulmonary circuit, and the left side of our heart pumps blood throughout the systemic circuit. So we'll be investigating these two circuits of blood flow today using this diagram here.

So what I want to do first is to label the different structures in our heart so that as we explain the pulmonary and systemic circuit you'll have a better understanding of what I'm talking about. So this chamber of our heart right here is our right atrium. Hope you can read that OK. And then this is our right-- I'm just going to abbreviate R for right-- ventricle. So then over here we have our left atrium and our left ventricle.

So as I had mentioned a few minutes ago, our heart is divided into four chambers and two halves. We have our left half of our heart and our right half of our heart. And each half is divided into an atrium, which is the upper chamber, and a ventricle, which is the lower chamber.

So we're going to start by talking about the pulmonary circuit. So the pulmonary circuit blood flow is the circuit that's pumped by the right side of our heart. So this side of our heart here is responsible for our pulmonary circuit of blood flow. So our pulmonary circuit delivers oxygen-lacking blood from the right side of our heart up to our lungs-- so this is labeled as lungs-- up to our lungs and then to the left side of the heart.

And then our systemic circuit delivers oxygen-rich blood from the left side of our heart throughout the body and then back to the right side of our heart. So when we're dealing with our pulmonary circuit, we're dealing with blood that is oxygen lacking.

So our pulmonary circuit, it has blood that's coming from the body. So this blood here, the oxygen that was in this blood has already been used up by the body and by its tissues. So this blood that's low in oxygen and that's oxygen lacking is delivered to the right atrium, moves into the right ventricle, and then is pumped up to the lungs.

Now, once it reaches the lungs, it will be able to latch onto more oxygen. It will become oxygen rich. And then it will flow into our left atrium down into our left ventricle. And from there, this oxygen-rich blood is pumped to our body's tissues. So our systemic circuit, then, is dealing with oxygen-rich blood.

So pulmonary circuit is delivering blood to the lungs to collect oxygen, and then our systemic circuit is delivering that oxygenated blood throughout our body. So this lesson has been an overview on the pulmonary and systemic circuits of blood flow.