anatomy and physiology of the heart

Anatomy and Physiology of the Heart: How the Heart Works for Dummies

anatomy and physiology of the heart


The heart can be best described as a pump, which is really the simplest description of this remarkable organ. It is a muscular organ the size of your fist that is located slightly left center in your chest. In this article I am going to go into the details about the structure and function or the anatomy and physiology of the heart.

 Some Facts About the Heart

The average heart pumps about 7,500 liters of blood throughout your body. It beats about 100,000 times per day, which is about 36 million times in a year.

Your blood carries oxygen and nutrients, which your body needs to survive. The cardiovascular system is made up of blood vessels called arteries, capillaries and veins, which pumps blood into every part of your body.


Coronary Arteries: How does the heart nourish itself?

The blood vessels that feed the heart with nutrients and oxygen rich blood are called coronary arteries. They nourish and extend over the surface of the heart and branch into smaller capillaries.


The heart anatomy for dummies


Electrical Conduction Pathway of the Heart

The electrical system of the heart that regulates it and keeps it beating. This electrical system is known as the conduction system of the heart.

Electrical impulses are generated in Sinoatrial node (SA node) located near the superior vena cava in the right atrium.

The SA node is the natural pacemaker of the heart. It initiates the heartbeat and determines the heart rate.

Electrical impulses coming SA node is sent to the atrioventricular node (AV node), which causes the atrium to contract.

Once the blood fills the ventricles, the signal are sent from the bundle of His to the purkinje fibers and then the ventricles contracts. And every contraction makes blood pump into our cardiovascular system.


Blood Flow Through the Heart

trace of blood flow through the heart

The heart is divided into left and right sides and has four separate chambers. The top two are called atria, and it is their job to collect blood. The bottom two are called ventricles, which pump the blood out.

Valves (tricuspid, pulmonary, mitral and aortic) are present in the heart. A valve is a one way pumps that make sure that the blood flows the right way.

The division of the heart into the left and right sides prevents mixture of oxygenated (oxygen rich) blood with deoxygenated (oxygen poor) blood.

Deoxygenated blood returning to the heart after circulating through the body comes in from the superior and inferior vena cava into the right atrium.

From the right atrium the blood is pumped through the tricuspid valves into the right ventricles.

The right ventricle pumps the deoxygenated blood through the pulmonary valves and the blood then passes through the pulmonary arteries to your lungs.

Every time you take a breath, oxygen moves from your lungs to your blood vessels and gets added to your blood, in this way the blood become oxygenated.

The oxygenated blood then moves out of the lungs through the pulmonary vein back into the left atrium of the heart.

Then the blood is pumped through the mitral valve into the left ventricles and pumped through the aortic valve and out of the heart through the aorta to the rest of the body.

This intricate system of pumping and circulation is continuous and repeats over and over again.

If you have any feedback, questions or concerns about this article. I would love to hear from you. Kindly leave your comments in the comments section below.

Thank you for reading!

20 thoughts on “Anatomy and Physiology of the Heart: How the Heart Works for Dummies”

  1. I was fortunate to see a film in 1966 of the first artificial heart valve implant surgery performed by Dr. Albert Starr in the early 60’s. (jeez, I’m old) Dr. Starr was in attendance at the showing of the film and narrated the action on the screen. Dr. Starr was the co-inventor of the world’s first artificial heart valve. 

  2. Hi, it’s really interesting to read about the function of a heart. It does a great job, so many pumping actions every day all year long.

    It’s amazing how nature came up with this kind of integrated systems, technology working for thousands of years for all kinds of creatures.

    I wonder why nature cannot regulate weather the way it regulates bodies haha, here starts the dry season again and water is going to be a problem soon.

    1. Hi Stefan,

      I am glad that you found the article interesting to read. The heart is truly amazing in its functions. Have a great day!



  3. This is a very informative post, easy to understand by laymen.It is so interesting to note that our heart is one of the vital organs in our body, meaning we cannot live without it.If it stops functioning normally, people will have lots of problems.Just curious, do you know why the heart beats fast if we see somebody that we like, a crush perhaps or somebody that we really like?Marita

    1. Hi marita,

      Yes the heart is one of the body’s vital organ. The heart beats faster when we see somebody we like because of that triggers the adrenaline rush. Adrenaline is a hormone that is also known as ephinephrine this hormone activates a sympathetic nervous system response, which causes your heart to beat faster, muscle strength and strong emotions etc. I hope that answers your question
      Have a great day!


  4. Hi Pam,

    What a neat read about the heart! It’s amazing that something the size of fist can pump 7,500 liters of blood and beat 36 million times a year. I now understand why you hear that the human body is an extraordinary. I am completely mesmerized by the natural electrical system that keeps your heart beating. 

    I actually understand the common terminology because of your thorough explanation.  I do have one question? When someone gets a pacemaker, is that to replace the SA node which is the natural pacemaker of the heart? 

    Thanks for posting. Super interesting. 


    1. Hi Kim,

      Yes the heart is such an amazing organ. To answer your question; People usually get a pacemaker when they have a heart condition where the natural pacemker of the heart which is the SA node has difficulty initiating the heart beat or they have a slower than normal heart rate, or arrhythmias which are abnormal heart rhythms.
      I hope that makes sense
      Have a great day!


  5. Great introduction to the workings of our heart. I got to see mine in the hospital under a ultrasound when I was having some issues breathing. Turned out my heart was perfect.

    Is the heart or the brain the most important in out bodies, or is it something else?

    Do type 2 diabetics have a higher risk of heart issues?  I am curious since I am one.

    Thanks for this education.

    1. Hi Curtis,

      I am so sorry to heart about your breathing issues. I hope you feel better now. However,It is so cool that you got to see yours. And yes the vital organs of the body are the Brain, Heart, Lungs, Kidney and liver. They are known as the 5 vital organs of the body because they do so much for us and are essential for our survival. I hope this answers your question. Have a great day!


  6. I Love the lessons this I went it through in school  I have since forgeten  how I our hearts works and how that organ is important for my survival  I believe this can be taken a lesson on how  we take ofour heart but more often than we take things for granted as if it a must our hearts to keep pumping the blood. I when does our relax or when is it less busy ?

    1. Hi Charles,
      I am so glad to hear that you loved the article. Must have been a good refresher for you. I hope you have a great day!


  7. I must say that this article is very helpful and informative Pam. I remember those days when I was learning about the heart on my biology class but I forget so many things about it. I like that you remind me about it as this organ is most important for a human and we should pay more attention to its health.

  8. You do a great job of explaining in terms non-medical people can understand.  When I was a kid my brother was born with transposed aorta and pulmonary arteries and I developed an interest in the workings of the heart at that time.  I recall that I had to read medical journals and pamphlets to get at the basic information that you have provided in concise sentences of only a few hundred words. It took a lot of time to find and digest the material. This is a great convenient service you are providing.  I’ll bookmark your site and check back when I have something to research and will have my kids get familiar with it, as well.  Thanks.

    1. Hi J52powell,

      Thank you for your comment! I am glad that you find the article relevant. Wow amazing! not everyone find the medical stufff interesting so I am glad that you do! Thank you so much and have a great day!



  9. What an enlightening and educational post about the anatomy of the heart and how it functions. 

    We all know that the heart is one of the most important organs (if not the most important organ) in the human body because the moment it stops functioning is also the time that physical life ends. Isn’t it amazing how a small organ such as the heart is able to pump 7.5 liters of blood and beats 100 thousand times per day? Wow, I must say, the heart is a hard-working organ  and so we must do all we can to take really good care of it. 

    1. Hi Alice,

      yes the heart is very hard work, work hard everyday to keep us alive. Thank you Alice for your comment. Have a great day!


  10. Hi Pam, I just read your article “How The Heart Works For Dummies”. Being a sportsman and a trainer/instructor I have always had an interest in how the body works. If the heart has to pump 7.5 litres and beats1000,000 time per day, it must have to work double time and a half in extreme endurance athletes. The human body is truly an amazing creation. Thank Pam

Leave a Reply to Alice Cancel Reply

Your email address will not be published. Required fields are marked *