The Inner Workings of the Human Heart - dummies

The Inner Workings of the Human Heart

By Sarah Samaan, Rosanne Rust, Cynthia Kleckner

Your heart is a remarkable organ. In its natural, healthy state, it beats strong and steady, delivering freshly oxygenated blood from your heart through your arteries to all your vital organs. After the blood is depleted of its life-sustaining oxygen, it’s recycled through the veins, transferred back to the heart, and delivered to the lungs to be resupplied with oxygen.

This cycle happens second after second, day after day, year after year.

To help you get a better mental picture (and understanding) of your heart as the extremely complicated yet compact organ that it is, think of it like the cardiologists do — as consisting of pumps, pipes, and electrical wiring.

  • Pumps: The pumps are made up of your left and right ventricles, as well as the smaller left and right atria. The left ventricle is what propels the blood through the aorta (a muscular artery resembling a garden hose), through an intricate network of arteries, and then to your entire body.

    Veins (less muscular than arteries) carry the blood back toward the heart, eventually dumping it back into the right atrium by way of the superior and inferior venae cavae. From the right atrium, blood is rhythmically released into the right ventricle, which sends it back to the lungs.

    From the lungs, the blood enters the left atrium on its way back to the left ventricle, and the cycle starts all over again. Weakening or stiffening of the pump can cause congestive heart failure.

  • Pipes: The pipes are your coronary arteries. These small yet very important blood vessels siphon off some of the blood from the aorta to feed the heart muscle. A blockage in one of these arteries will lead to a heart attack.

  • Wiring: The wiring is what keeps your heart ticking in rhythm. Your heart is full of electrical tissue. Although the electricity usually flows in an orderly fashion, sometimes the wiring gets old and frayed, and that deterioration can cause the heart to slow down or beat erratically.

    Other times, you may have a short circuit or a rogue patch of electrical tissue that fires out of time with the rest of the heart, causing your rhythm to go haywire.

    [Credit: Illustration by Kathryn Born]
    Credit: Illustration by Kathryn Born

Problems with one part of the heart can affect its other functions. For instance, a heart attack may damage the wiring as well as the pump. Hypertension can cause the pump to become weak or stiff, which in turn can lead to electrical problems. But even when the heart becomes damaged or overworked, it does its best to keep on ticking.