Blood Flow Through The Heart: A Simple 12 Step Diagram
Blood flow through the heart made easy! This video provides a simple step-by-step diagram of the cardiac blood flow and a chart of the circulation pathway. Includes the anatomy of the heart and an animation quiz at the end in order to test your knowledge!
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Blood Flow Through the Heart
Blood flow through the heart is made easy in this post!
Using a simple diagram to show the order in which blood flows through the heart, we will walk through the cardiac circulation pathway in 12 simple steps.
As with every EZmed post, we have some simple tricks and charts that will help you remember the anatomy, physiology, and function of the right and left side of the heart.
In just a few minutes, you will be able to label the entire diagram shown below!
The video above also provides an animation at the end to quiz yourself and test your knowledge!
Let’s get started!
Diagram: Blood flow through the heart, cardiac circulation pathway, and anatomy of the heart.
Anatomy of the Heart
The anatomy of the heart was made easy in a previous EZmed video and post, where we learned tricks to remember the main cardiac structures shown below.
Check out the anatomy of the heart linked below, as that will be a great review of the main cardiac structures before learning the blood flow!
Heart Anatomy: Labeled Diagram, Structures, Function, and Blood Flow
Diagram: Anatomy of the heart and main cardiac structures including the heart valves, chambers (atria and ventricles), and great vessels.
We then simplified the anatomy of the heart even further with the below cartoon diagram and 2x2 table.
Diagram: Anatomy of the heart and chart showing the main cardiac structures including the atria, ventricles, and heart valves.
Now that you have reviewed the anatomy of the heart using the above link, we are going to discuss the blood flow through those cardiac structures step by step!
Right vs Left Side of the Heart
The easiest way to understand the blood flow through the heart is to divide the heart into 2 sides.
We first have the right side of the heart shown in blue below.
There are 6 main steps or structures in which blood flows through the right side of the heart.
Next, we have the left side of the heart shown in red.
Similar to the right side, there are 6 main steps or structures in which blood flows through the left side of the heart.
Diagram: Blood flow steps through the right and left side of the heart, cardiac anatomy and structures, and cardiac circulation pathway.
12 Step Guide - Cardiac Blood Flow
We are going to walk through the 12 steps of the blood flow through the heart one-by-one using the below cartoon image.
Once we have a good understanding of that, we will then apply that information to the realistic diagrams shown at the beginning of this post.
One of the first things you will notice if you look at the 12 steps is the pattern between the right and left side of the heart is similar.
Step 1 and 6 involve a blood vessel, which makes sense as this is how blood enters and exits that side of the heart.
Steps 2-5 involve a chamber, valve, chamber, and valve.
So if you remember this general pattern, it will help you recall the order in which blood flows through each side of the heart.
Right Side of the Heart
SVC/IVC
Right Atrium
Tricuspid Valve
Right Ventricle
Pulmonary Valve
Main Pulmonary Artery
Left Side of the Heart
Pulmonary Veins
Left Atrium
Mitral Valve
Left Ventricle
Aortic Valve
Aorta
Diagram: Blood flow through the heart in 12 steps, cardiac anatomy and structures, and cardiac circulation pathway.
Blood Flow - Right Side of the Heart
Let’s now walk through the above 12 steps beginning with the right side of the heart.
1. Superior Vena Cava and Inferior Vena Cava
Step 1 involves the superior vena cava (SVC) and inferior vena cava (IVC).
They are the main blood vessels that carry the deoxygenated venous blood from the rest of the body to the right side of the heart, specifically the right atrium.
The superior vena cava is located superiorly, and it carries the deoxygenated venous blood from the upper body to the right atrium.
Conversely, the inferior vena cava is located inferiorly, and it carries the deoxygenated venous blood from the lower body to the right atrium.
2. Right Atrium
Step 2 involves the right atrium, the first chamber of the heart in which the deoxygenated blood from the rest of the body enters.
The deoxygenated venous blood carried by the SVC and IVC enters the right atrium.
3. Tricuspid Valve
Step 3 involves the tricuspid valve.
During diastole, when the heart is relaxed and filling with blood, the deoxygenated blood from the right atrium will flow to the right ventricle.
In doing so, the blood travels through the tricuspid valve located between the right atrium and right ventricle.
Make sure to check out the below EZmed post on the cardiac cycle, where we discuss systole, diastole, and the changes in the pressure in heart during these phases!
The Cardiac Cycle: From Diastole to Systole
4. Right Ventricle
As we alluded to above, step 4 involves the right ventricle.
During diastole, the deoxygenated blood from the right atrium travels through the tricuspid valve and enters the right ventricle.
5. Pulmonary Valve
Step 5 involves the pulmonary valve, also known as the pulmonic valve.
During systole, when the heart (specifically the ventricles) are contracting, deoxygenated blood from the right ventricle will be pumped forward from the right ventricle to the main pulmonary artery.
In doing so, the deoxygenated blood travels through a valve known as the pulmonary valve located between the right ventricle and main pulmonary artery.
6. Main Pulmonary Artery
Step 6 involves the main pulmonary artery, also known as the pulmonary trunk.
During systole, the deoxygenated blood from the right ventricle travels through the pulmonary valve and enters the main pulmonary artery.
The function of the main pulmonary artery is to carry deoxygenated blood from the right side of the heart to the lungs to become oxygenated.
The main pulmonary artery splits into the right and left pulmonary arteries, which we will better see in later images.
Diagram: Blood flow through the right side of the heart involving the following cardiac structures: superior vena cava (SVC), inferior vena cava (IVC), right atrium (RA), tricuspid valve (TV), right ventricle (RV), pulmonary valve (PV), and main pulmonary artery (PA).
Trick to Remember the Right Side
The main goal of the right side of the heart is to pump the deoxygenated blood it receives from the rest of the body to the lungs to become oxygenated.
A trick to remember the function of the RIGHT side of the heart is it pumps blood “RIGHT” to the lungs.
Diagram: Trick to remember the function of the right side of the heart is to pump deoxygenated blood to the lungs - Blood goes “RIGHT” to the lungs.
Blood Flow - Left Side of the Heart
Now that the deoxygenated blood has become oxygenated in the lungs, we need be able to pump the oxygenated blood to the rest of the body - which brings us to the left side of the heart.
Again, you will see a similar general pattern with the left side of the heart as we did with the right side (blood vessel, chamber, valve, chamber, valve, blood vessel).
1. Pulmonary Veins
Step 1 involves blood vessels, similar to what we saw with step 1 in the right side of the heart.
The pulmonary veins carry oxygenated blood from the lungs to the left side of the heart, specifically the left atrium.
There will be better images of the pulmonary veins shown in the images later in this post.
2. Left Atrium
Step 2 involves the left atrium, the chamber of the heart that receives oxygenated blood from the lungs via the pulmonary veins.
3. Mitral Valve
Step 3 involves the mitral valve.
During diastole, when the heart is relaxed and filling with blood, the oxygenated blood from the left atrium will flow to the left ventricle.
In doing so, the blood travels through the mitral valve located between the left atrium and left ventricle.
4. Left Ventricle
As we alluded to above, step 4 involves the left ventricle.
During diastole, the oxygenated blood from the left atrium travels through the mitral valve and enters the left ventricle.
5. Aortic Valve
Step 5 involves the aortic valve.
During systole, when the heart (specifically the ventricles) are contracting, oxygenated blood from the left ventricle will be pumped forward from the left ventricle to the aorta.
In doing so, the oxygenated blood travels through a valve known as the aortic valve located between the left ventricle and aorta.
6. Aorta
Step 6 involves the aorta.
During systole, the oxygenated blood from the left ventricle travels through the aortic valve and enters the aorta.
The function of the aorta is to carry oxygenated blood from the left side of the heart to the rest of the body.
Diagram: Blood flow through the left side of the heart involving the following cardiac structures: pulmonary veins (PV), left atrium (LA), mitral valve (MV), left ventricle (LV), aortic valve (AV), and aorta.
Trick to Remember the Left Side
The main goal of the left side of the heart is to pump the oxygenated blood it receives from the lungs to the rest of the body in order to perfuse tissues and organs.
A trick to remember the function of the LEFT side of the heart is it pumps blood that has “LEFT” the lungs.
Diagram: Trick to remember the function of the left side of the heart is to pump oxygenated blood to the rest of the body - Blood that has “LEFT” to the lungs.
Blood Flow of the Heart Review
Let’s now use the 2x2 table we made in the anatomy of the heart post, and this will give us another way to visualize the blood flow through the heart.
Right Side
First, we have the SVC and IVC that carry deoxygenated venous blood from the rest of the body to the right atrium.
Blood will then flow from the right atrium, through the tricuspid valve, and enter the right ventricle.
The deoxygenated blood will then exit the right ventricle, travel through the pulmonary valve, and enter the main pulmonary artery to ultimately be delivered to the lungs to become oxygenated.
Left Side
The oxygenated blood will then travel from the lungs to the left atrium via the pulmonary veins.
Blood will then flow from the left atrium, through the mitral valve, and enter the left ventricle.
The oxygenated blood will then exit the left ventricle, travel through the aortic valve, and enter the aorta to be delivered to the rest of the body.
Diagram: Blood flow through the heart, cardiac circulation pathway steps, and cardiac anatomy and structures. Blue arrows (deoxygenated blood); Red arrows (oxygenated blood).
Now that we have a good understanding of the blood flow through the heart using the cartoon diagrams, we can apply it to a more realistic image of the heart.
The blue arrows represent the flow of deoxygenated blood through the right side of the heart.
The red arrows represent the flow of oxygenated blood through the left side of the heart.
Diagram: Blue arrows demonstrate flow of deoxygenated blood through the right side of the heart. Red arrows demonstrate flow of oxygenated blood through the left side of the heart.
Lastly we can revisit the original diagram shown at the beginning of this post and you should be able to understand and label the entire image.
Diagram: Blood flow through the heart, cardiac circulation pathway, and the main cardiac structures and anatomy.
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