Why Does The Heart Make A Lub Dub Sound _best_ -

The familiar "lub-dub" sound isn't the heart muscle contracting, nor is it blood simply sloshing around. It is the sound of heart valves snapping shut .

Think of it like clapping your hands: the sound isn't from the movement itself, but from the instant two surfaces meet. In the heart, that meeting is the forceful closure of valves designed to keep blood flowing in one direction. why does the heart make a lub dub sound

The heart doesn't "beat" — it valves shut. The "lub" is the sound of the top valves closing as the bottom chambers squeeze. The "dub" is the sound of the exit valves closing as the bottom chambers relax. The familiar "lub-dub" sound isn't the heart muscle