What Produces The Lub Dub Heart Sounds [top] May 2026

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.

The "Dub" is the sound of the escape hatches closing after the blood has left. Part 4: The Bizarre Physics of the Silent Gap Notice the rhythm: Lub...Dub...pause...Lub...Dub...pause. what produces the lub dub heart sounds

To stop this backflow, the (pulmonary and aortic) snap shut. Unlike the fleshy AV valves, these look like three tiny crescent moons (hence "semilunar") shaped like a Mercedes-Benz logo. The "Lub" is the sound of the exit