GROSS ANATOMY

Detailed explanation-1: -This sound comes from the valves shutting on the blood inside the heart. The first sound (the lub) happens when the mitral and tricuspid valves close. The next sound (the dub) happens when the aortic and pulmonary valves close after the blood has been squeezed out of the heart.

Detailed explanation-2: -The sounds are often described as a constant “lub-dub, lub-dub.” The first “lub-dub” is the sound of the mitral and tricuspid valves closing. The second “lub-dub” is the sound of the aortic and pulmonary valves closing soon after.

Detailed explanation-3: -Summary. The familiar ‘lub-dub’ sound of the heartbeat is caused by the rhythmic closing of the heart valves as blood is pumped in and out of the chambers. A heart murmur is a whooshing, humming or rasping sound between the heartbeat sounds. This is caused by noisy blood flow within the heart.

Detailed explanation-4: -When the valves between the upper chambers (atria) and lower chambers (ventricles) close, a “lub” sound is heard. When the valves in the pulmonary and aortic arteries leaving the heart close, a “dub” sound is heard followed by a longer pauseLub-DubLub-Dub.