Easy Anatomy: Understanding How the Human Heart Works
How the Human Heart Works
The human heart is one of the most amazing and essential organs in the human anatomy. Many people know that it pumps blood and is located on the left side of the chest, but not much more. The heart is actually very complex (I will go into more detail in later hubs), but I hope to keep this hub as a relatively simple and quick overview of how the heart works, what it does and some of the main sections of the heart.
The human heart is about the same size as a fist and it is located on the left side of the chest. This is pretty straight forward, but there is one common misconception: Many people tend to think that the human heart is all the way to the left side of the chest, but it is more accurate to say that it is in the middle of your chest favoring the left side (Next time you stand for the “National Anthem” put your right hand a bit closer to your sternum, if you wish to rest it over your heart).
The heart is made up of four separate chambers. Each chamber is separated by a one-way valve to avoid any backflow of blood. The top two chambers are called atria (singular form: atrium) and the bottom two chambers are called ventricles. The purpose of the heart is to pump oxygen poor blood to the lungs where the blood cells receive oxygen and to pump this oxygen rich blood into the rest of the body.
The Path of Blood Flow
Before we can go much further in learning about the heart, we should have an understanding of the path the blood goes through to get from one side of the heart to the other.
1. The first step is that oxygen poor blood flows into the right atrium through the inferior and superior vena cava’s (the superior vena cava dumps blood into the heart from the head, chest and arms and the inferior vena cava dumps blood from the lower body).
2. The blood then flows through the bicuspid atrioventricular valve (the first of the one-way valves mentioned earlier) and into the right ventricle.
3. Next, blood is pushed through the semilunar valve (second one-way valve) into the pulmonary trunk. The pulmonary trunk leads to the lungs.
4. Once the blood has become oxygen rich, it flows through the pulmonary veins and into the left atrium.
5. After the left atrium, the blood is pushed through the tricuspid atrioventricular valve (the third one-way valve) and into the left ventricle.
6. The blood is now oxygen rich and only one step away from entering the rest of our body. The blood is finally pushed from the left ventricle into the aorta.
· The 4 chambers of the heart are so important because they ensure that oxygen poor blood does not mix at all with oxygen rich blood.
· The heart actually pumps twice each time we count one heart beat (you may recall hearing an over dramatized “lub dub” in a suspenseful movie). The “lub” sound is made by the atrioventricular valves closing and the “dub” sound is made by the semilunar valves closing.
· The heart is extremely efficient: A person who has a heart rate of 70 beats per minute pumps an average of 5 ¼ liters of blood in just one minute. That is nearly all of the body’s blood being pumped through the heart every minute!
I hope to cover more in-depth aspects of the heart soon! I will look into how each heart beat is triggered and how our heart rate is determined as well as how our heart itself receives oxygen rich blood from itself.
Thanks for reading!