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Heart: structure and function

Heart: structure and function

Description:

This lesson will identify the major structures of the heart and define their specific role in the overall functioning of the heart.

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Tutorial

The Structure and Function of the Heart

Source: Heart Image from Adobe Illustrator; Public Domain

Video Transcription

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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.

TERMS TO KNOW
  • Myocardium

    The muscular tissue that composes the heart.

  • Atrium

    The right and left upper chambers of the heart.

  • Ventricle

    The right and left lower chambers of the heart.

  • Atrioventricular Valve

    A valve that allows blood to flow from the atrium to the ventricle while preventing backflow of blood.

  • Pulmonary Valve

    A valve that allows blood to flow from the right ventricle to the pulmonary artery while preventing backflow.

  • Aortic Valve

    A valve that allows blood to flow from the left ventricle to the aorta while preventing backflow.

  • Aorta

    An artery that delivers blood to the systemic circuit.

  • Septum

    A wall of tissue that separates the right and left halves of the heart.

  • Superior Vena Cava

    A vein that delivers deoxygenated blood from the upper portion of the body to the right atrium.

  • Inferior Vena Cava

    A vein that delivers deoxygenated blood from the lower portion of the body to the right atrium.

  • Pericardium

    A fluid filled sac that surrounds the heart and provides protection and lubrication.