The Human Heart Explained So That Even A 5 Year Old Can Understand

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The Human Heart Explained So That Even A 5 Year Old Can Understand

By Joe Burgett - August 7, 2020

Heart Size

The size of the human heart can differ somewhat. Most hearts grow along with the person as they age. Hearts range around 5 inches (12 cm) in length, 3.5 inches (8 cm) wide, and 2.5 inches (6 cm) in thickness. Male and Female hearts weigh a bit differently. Male hearts range from 10 to 12 ounces (280-340 grams) while Female hearts range from 8 to 10 ounces (230-280 grams)

While some sizes can be problematic and be a sign of sickness, this is not always the case. In fact, many athletes have bigger hearts. Since our hearts often work like muscles, a well-trained athlete can have a larger heart than average due to the amount of exercise they get. Like a skeletal muscle, the heart will get a bit larger the more exercise a person puts it through. Yet you do not want it to get too large, which is why you might hear about being healthy enough for specific activities.

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Heart Shape and Location

The shape was described as “like a pyramid” by Hippocrates but it’s often described as a Cone shape today. They aren’t too different clearly. Therefore no, the shape of our actual heart is not “heart-shaped,” funny enough. The location of our heart is toward the middle of our chest and lies behind the sternum and ribcage.

However, the lower tip of the heart is toward the left side of the sternum between our 4th and 5th ribs. This is likely why so many assume it’s located on the left side when it’s not. For years, we assumed the left side made the most sense. Yet there is no real reason for this except for how nerves made us feel it was toward the left. Therefore, when you pledge allegiance to the flag, your hand should go over the middle of your chest, not the far left.

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Heart Chambers

Our heart has four total chambers. They are comprised of two upper chambers and two lower chambers, with the upper and lower doing different things. The upper chambers, known as the right and left atria, receive incoming blood from the body. Yet the lower chambers, known as the right and left ventricles, pump out blood from the heart to the body.

Our valves then serve as gatekeepers that allow proper flow with our blood and keep it going in the right direction. This is essential because if the valves did not do this our bodies could literally shut down. That is why, when even one does not operate correctly, surgery is required to fix it.

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Heart Valves

There are also four valves too, one for every chamber. These are comprised of the Mitral Valve, Tricuspid Valve, Aortic Valve, and Pulmonic Valve. The Mitral and Tricuspid valves are located between the upper chambers while the Aortic and Pulmomic Valves are located between the lower chambers.

Perhaps something you may not know here is that the sound of our heartbeat is produced by the opening and closing of our heart valves. This can be quite weird and partly, even kind of trippy to the heart. One would assume the beat of the heart comes from other factors. Yet this is why doctors check your heartbeat when you go in to be seen. Valve issues result in several heart-related illnesses, and that means hearing your heartbeat can be critical for doctors to know how to help you.

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Heart Walls and Layers

While most naturally assume there is only one heart wall, there are actually three total heart walls. They come together to help form a thick heart that protects itself from possible damage. The external layer of the heart wall is called the Epicardium while the middle layer is known as the Myocardium. Finally, the inner layer is called the Endocardium. The Epicardium is thin and transparent, made from delicate connective tissue. The Myocardium is made of cardiac muscle tissue and tends to make up the majority of our overall cardiac wall. It’s also responsible for its own pumping action.

Meanwhile, the Endocardium is made of a thin layer of endothelium that overlies another thin layer of connective tissue. This provides a smooth overall lining for the four chambers of the heart, while also covering all four heart valves too. The Endocardium is also connected to and is continuous with the endothelial lining of the large blood vessels that are attached to the heart itself.

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Arteries Of The Human Heart Part 1

The arteries of the human heart are as follows: The aorta, pulmonary trunk, right and left pulmonary arteries, right coronary artery, and the left main coronary artery. The aorta is located near the top section of the heart and happens to be the heart’s main artery. It supplies oxygenated blood to our circulatory system.

When blood leaves the aortic valve, it travels through the aorta itself where it then exits our brain, muscles, and cells. Whenever you see “pulmonary” it tends to mean something related to the lungs. That is exactly what the pulmonary trunk, as well as the right and left pulmonary arteries, affect.

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Arteries Of The Human Heart Part 2

The pulmonary trunk is located usually near the top right of the heart and then splits off into the right and left pulmonary arteries. The left is a bit smaller than the right but it does just as well as its “right” neighbor. They both pretty much do as you’d imagine, carry blood to the lung the name suggests.

The right coronary artery and left main coronary artery each feed blood into their designed sections of the heart itself. The left is pumping to the left side and the right is pumping to the right. They both come out of the aortic valve with the left coming out of the left cusp of this valve and the right coming from the right cusp of the same valve.

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Veins Of The Human Heart Part 1

The veins of the human heart are as follows: Superior Vena Cava, Inferior Vena Cava, right and left pulmonary veins, Great Cardiac Vein, Middle Cardiac Vein, Small Cardiac Vein, and Anterior Cardiac Veins. The Vena Cava veins are pretty straightforward. The Superior returns deoxygenated blood from the systematic circulation to our right atrium.

It receives a venomous return from the upper half of the body. Meanwhile, this happens at the lower end regarding the Inferior. The Inferior also takes blood to the right atrium but it comes from the middle and lower parts of the body. Both of the Vena Cava are crucial to the function of our hearts.

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Veins of The Heart Part 2

Of course, our Pulmonary Veins are similar to Pulmonary arteries. The right and left veins essentially make up four veins, with two flowing to each lung. They drain into the heart’s left atrium and are part of our pulmonary circulation. The Great, Middle and Small Cardiac Veins return deoxygenated blood from the myocardium to the right atrium.

This same blood flows back to the lungs for reoxygenation and removal of carbon dioxide. All end at the Coronary Sinus too. The Anterior Cardiac Veins mostly are comprised of between two and five small vessels that collect blood from the right ventricle and open into the right atrium. Yet it does not end at the Coronary Sinus but rather drains into the anterior wall of the right atrium.

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The Human Heart Nerves and Sinus Node Part 1

There are technically only two main nerves in the human heart. They are known as the Accelerans Nerve and Vagus Nerve. Each is pretty important and likely does a lot more than you might think. Each nerve is affected by the nervous system, of course. Yet the heartbeat we have is set up by something known as a sinus node.

This node is made up of a group of cells located in the wall of the right atrium. They have the ability to randomly produce electrical impulses that travel through the heart via its electrical conduction system. Ultimately, that causes our heart to contract. When a sinus node is not in play for someone, a pacemaker does the job for them.

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The Human Heart Nerves and Sinus Node Part 2

When it comes to nerves, they are also affected by hormones in the blood and the amount of blood being returned to the heart. The Vagus Nerve is what slows down our heart rate, as it uses acetylcholine to accomplish this. Meanwhile, the Accerlans Nerve speeds it up by using noradrenaline.

This actually increases blood flow helping a person prepare for an increase in possible activity. These nerves are also part of the autonomic nervous system, which is part of the infamous “Fight or Flight” System. Medical professionals even have both Acetylcholine and Noradereline on hand to help in needed situations.

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Interesting and Surprising Heart Facts

One thing we always like to do when explaining an organ, especially one such as the heart, is to mention some compelling information you may not know. For example, did you know that the human heart pumps 2,000 gallons of blood per day on average? You may also not know that a woman’s heart beats faster than a man’s on average.

Men and women are both capable of having heart trouble yet men are more likely to have heart attacks than women. Yet women are more than 40% of all heart attack deaths annually, meaning heart attacks affect them far worse. Women are also older than men are when they get heart attacks, which could also be a key reason for the higher fatality rate.

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Heart Differences In Men and Women Part 1

A woman’s heart tends to be smaller than a man’s. The walls that divide some of the chambers of the heart are thinner for women versus men too. While a woman’s heart pumps faster than a man’s, it also ejects around 10% less blood with each squeeze of the heart. This can, sometimes, affect a woman’s cardio versus a man’s. However, as mentioned previously, a woman who exercises her heart can make it larger.

Theoretically, this can even her up with a regular man’s heart size. You already know that men might be more likely to get a heart attack while women die more from them. However, did you know the way in which each sex has a heart attack differs? Men often will have chest pain as well as pain radiating down the left arm. Meanwhile, women might get shortness of breath but could also have pain in the back, neck, or jaw accompanied by major fatigue or tiredness.

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Heart Differences In Men and Women Part 2

Why are men more likely to have a heart attack or high blood pressure? This could be due to how stress impacts men differently. When a woman is stressed, her pulse rate will rise while her heart pumps more blood. Yet when a man gets stressed, the arteries of the man’s heart constrict, raising his blood pressure.

Due to societal pressures as well as those men put on themselves, stress is an issue among men worldwide. Therefore, high blood pressure is also higher among men too. This makes sense in theory. Of course, untreated long-term high blood pressure can lead to heart attacks. More and more women are also seeing heart problems directly related to stress. Yet due to most women being able to handle stress in a slightly healthier way heart-wise, heart attacks from stress are not as common.

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How The Heart Became Associated With Love Part 1

For a, seemingly, endless period of time, we have connected the heart with love. However, there is no reason for this as we proved centuries ago that consciousness and emotions were all brain-driven. Ancient Egyptians, Chinese, and Romans all believed the heart and love had some connection.

In fact, the Romans believed that a vein of the heart extended to the fourth finger on a person’s left hand. This is, of course, not actually the case. However, that is why when a person gets engaged or married, it is now a tradition to put the ring on a person’s left hand, on the fourth finger.

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How The Heart Became Associated With Love Part 2

Some believe love became connected to the heart due to how we react to someone we find attractive. When this happens, our brain releases hormones. This sends a message to our blood and heart that can cause hormones to be released from the autonomic nervous system. That is why men, for example, might get an erect penis.

At the same time, both men and women might experience faster heartbeats due to the noradrenaline released. It’s easy to see how, knowing this, ancient people believe there was a connection. While people did eventually realize the differences between the heart and brain, we continue to associate our hearts with the emotion of love. Sometimes, old habits die hard, or they don’t die at all.

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You Really Can Have A Broken Heart and Die From It

While some believe that there is no such thing as a broken heart, the facts say otherwise. You can actually have a broken heart, but it’s technically not the cartoonish break. There aren’t any arrows in it either, cupid fans. We have already established in the past that there are connections between the brain and the heart.

However, this is a pretty big deal because it means that things like depression can affect your heart too. Doctors refer to this as “Broken Heart Syndrome.” Yet it’s also called Stress-Induced Cardiomyopathy. It can affect anyone, even those with a completely or relatively healthy heart, as well as those young and old.

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How Broken Heart Syndrome Affects Us

As one of the names suggests, it is typically triggered by stress. This is due to a sudden increase in stress hormones that put a lot of harmful pressure on the heart. Women are more likely than men to experience Broken Heart Syndrome but men CAN still experience it. The Syndrome typically causes horrific chest pain and often gets mistaken for a heart attack.

This is due to symptoms being incredibly similar, of course. However, there are thankfully no blocked arteries with Broken Heart Syndrome. That means most people tend to survive this and recover in a few weeks. In others, it can be deadly as it can cause sudden and severe heart muscle failure. Therefore, when your friend says they have a broken heart, take it seriously.

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Ways You Can Protect Your Heart Part 1

If you want to properly protect your heart so that you can live for many years to come, there are a few ways that can be accomplished. First, you should be sure to get proper sleep. In fact, prolonged lack of sleep has been known to cause irregular jumps in a person’s heartbeats. This is known as Premature Ventricular Contraction and it can be a big problem.

When they say laughter is the best medicine, it’s technically not a lie. It’s also a great preventative too. Laughter has been known to reduce stress and even boost your immune system. Therefore, when you feel down, avoid sad music. Instead, watch a comedy movie or stand-up special. Your heart will thank you later.

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Ways To Protect Your Heart Part 2

Be sure to eat as healthy as you can and go each year to proper check-ups from your doctor to make sure everything is working as it should. Do your best to stay away from hardcore drugs as well as recreational drugs, even those such as cannabis. When you use marijuana, it puts stress on your heart.

It can cause some issues with the heart such as increased blood pressure, arrhythmias, and even put you at greater risk of heart attack and stroke. Clearly, hardcore drugs like cocaine, meth, and more are obviously bad for you too. While cannabis is nowhere near as bad as those, it still can be bad for your heart. Therefore, it’s best to avoid it if you have any heart condition. Also, things like exercise can be incredibly helpful for your heart long-term!

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