What Produces The Lub Dub Heart Sounds //free\\ (2025)

Place your hand on the left side of your chest. Feel that? Thump-thump... thump-thump.

The chaos is the Lub-Dub. The first sound, "Lub" (clinically known as S1), marks the beginning of systole —the phase where the heart squeezes blood out . what produces the lub dub heart sounds

But the truth is far stranger and more fascinating. The "Lub-Dub" isn't the sound of muscle flexing. It’s not blood rushing through pipes. And it’s definitely not the heart "pumping." Place your hand on the left side of your chest

Then comes (S2), marking the end of systole and the beginning of diastole (relaxation). thump-thump

The "Lub" is the sound of the exit doors closing just as the heart tries to pump. Part 3: The "Dub" (The Escape Hatch Snap) After the "Lub," the ventricles continue to squeeze. They blast blood out through two other doors: the pulmonary valve (to the lungs) and the aortic valve (to the body). For a brief moment, the heart is emptying.