Valentine’s Day is just around the corner: a time of cards, candy, poems, and hearts adorning every door, window, and wall. While our hearts are often associated with love, they also have one of the most important roles in the human body. Let’s take a closer look at the heart’s function and anatomy.

Heart Shapes and Basics

Contrary to what is depicted in cartoons and popular culture, the heart is shaped like a cone. The apex of the “cone” points down and to the left. It’s hollow and located behind the breastbone, just between the lungs and above the diaphragm. About two-thirds of the heart is located to the left of your body. heart

In terms of size, the heart is roughly the size of a balled up fist, measuring 2.5 inches deep, 5 inches long, and 3.5 inches wide. On average, a man’s heart weighs about 10.5 ounces, while a woman’s heart weighs 9 ounces.
Proportionally, the heart is less than half a percent of your total body weight, but it is also the body’s most powerful muscle. Such a tiny organ is responsible for pumping blood and oxygen throughout all parts of your body.

Heart Parts

The heart is composed entirely of cardiac muscle that gives it the power to contract and expand and synchronize heart beats. The heart’s wall is divided into three layers:

  • Epicardium: the outer layer that protects the heart from sustaining damage
  • Myocardium: the middle layer composed of muscle
  • Endocardium: the smooth, inner lining of the heart that connects with the inner lining of blood vessels

The inside of the heart is divided into four chambers:

  • Right atrium
  • Right ventricle
  • Left atrium
  • Left ventricle

Blood passes through each chamber via one-way valves, much like the taps on a faucet, which prevent blood from flowing backwards. As each chamber contracts, the valve opens at its exit. At the end of the contraction, the valve closes. The four valves are:

  • Tricuspid valve located at the exit of the right atrium
  • Pulmonary valve at the exit of the right ventricle
  • Mitral valve located at the exit of the left atrium
  • Aortic valve at the exit of the left ventricle

Let It Flow

Blood flow is the name of the game, and the heart is the main player. All your blood enters through two veins located on the right side of the heart: the superior vena cava and the inferior vena cava. The superior vena cava takes blood from the top half of your body, while the inferior vena cava collects blood from the lower half.

From these two veins, your blood enters the right atrium. The right atrium contracts and sends blood through the tricuspid valve to the right ventricle. The right ventricle contracts and sends the blood through the pulmonary valve, through the pulmonary artery, and into the lungs.

Why does blood need to make a pit stop at the lungs? Well, blood that returns from the body is actually pretty lacking in oxygen. In order to get a refill, the blood stops by the lungs before moving on to the left side of the heart.

From the lungs, the blood reenters the heart through the pulmonary veins into the left atrium. It then goes through the mitral valve into the left ventricle and then through the aortic valve into the aorta. The aorta is the main artery of the body. It takes all of the oxygen-rich blood that the heart has pumped and distributes it to all the other organs, tissues, limbs, and body parts.

Where the Heart Gets Its Blood

Like all your other organs, your heart needs blood to get all that oxygen and nutrients. Although all your blood passes through your heart, it doesn’t actually use any of the blood that flows through it. The blood that supplies the heart with oxygen and nutrients is transported through coronary arteries. About 4 to 5 percent of your heart’s total blood output ends up in the coronary arteries.

You have two main coronary arteries, the left main and the right. The left main can be broken up into the left anterior branch and the left circumflex.

The main thing you have to watch out for is coronary artery disease, which is caused by a blockage in the arteries. A partial blockage prevents your heart from getting enough blood, a big problem considering how much your heart exerts itself. This chest pain is described as angina. More severe obstructions can lead to unstable angina. Complete blockage leads to an all-out heart attack. Blockages are composed of plaque and cellular waste products. Regular exercise and a heart-healthy diet are the most effective ways to prevent coronary artery disease.

Love and the Heart

It’s hard to say why love is so often associated with the symbol of the heart. Love has very real physiological effects on the brain, though the heart feels many of the side effects. For example, a racing heart when you see that special someone is caused by an outpouring of adrenaline. Research also shows that many people have lower blood pressure when they are with their romantic partners. Even in newer relationships, the “fresh love” that partners feel for each other can actually shield stress.
So this Valentine’s Day, remember to show some love to your heart. Among all the sweet pink and red decorations, festivities, and treats, our hearts are doing a lot of work!

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