The lub-dub sound of the heart is caused by the closing of the heart valves during the cardiac cycle.
The first sound, “lub,” marks the beginning of —the phase where the heart squeezes blood out to the body. lub-dub sound of heart is caused by
Valves closing silently would be ideal for efficiency, but the human body is a fluid system. When flaps of tissue snap shut, they vibrate. That vibration travels through the blood and chest wall, becoming the sound we hear. The lub-dub sound of the heart is caused