by Bill Georato

Created on: June 30, 2010

THE HUMAN HEART

The human heart, which is about the size of your fists, is the pump that keeps your blood flowing, much like the fuel pump in your car. It is the central feature of your cardiovascular system (the cardio refers to heart), and it keeps beating every moment of your life.  These paragraphs will explore this most important muscle.

LOCATION AND DIMENTIONS

The human heart is located in the chest, slightly left of the breastbone (sternum), between the lungs. The heart on average weighs 7 to 15 ounces, and, over the course of its life, will beat nearly 4 billion times. In fact, it beats approximately 100,000 times a day—72 beats per minute- pumping in that time about 2,000 gallons of blood. That means over a lifetime (figure an average of 70 years), the heart will pump over 250,000 gallons!

ANATOMY OF THE HEART

The heart is a very complicated “complex”, comprising more than just the heart itself. Let’s look at how it all fits together.

The Pericardium—this is a double layered sac, with fluid filling the space in between the layers. Its purpose is to protect the roots of the major heart blood vessels. The inner layer is attached to the heart, and the outer layer is attached to the spinal column and other locations.

The Inferior/Superior Vena Cava—these are two of the body’s major veins, which bring oxygen poor blood from the upper (superior) and lower (inferior) parts of the body.

The Aorta—this is the body’s major artery, which brings oxygen rich blood out of the heart to the rest of the body.

The Pulmonary Arteries—these take blood from the heart to the lungs to pick up oxygen.

The Pulmonary Veins—these return oxygen rich blood back to the heart from the lungs.

Finally, we get to the heart itself. The heart is made of four chambers, all separated by valves. The upper chambers are called the left and right atria (singular, atrium). The lower chambers are the right and left ventricles.

The right atrium takes blood from the body, which is now oxygen poor, and forces it through the tricuspid valve into the right ventricle. The right ventricle pumps the blood through the pulmonary valve into the lungs. Upon returning from the lungs, the now oxygen rich blood reenters the heart into the left atrium, and finally flows through the mitral valve into the right ventricle, through the aortic valve,  and out into the body. The left ventricle is the heart’s strongest chamber.

So,

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