ANATOMY

Detailed explanation-1: -The first sound, a low-pitched, slightly prolonged “lub, ” occurs when the atrioventricular valves close as the ventricles of the heart begin to contract. After a brief pause, this sound is followed by a sharper, higher-pitched “dup, ” produced by closure of the aortic and pulmonary valves.

Detailed explanation-2: -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-3: -These are called Lub-Dub noises by doctors. 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.

Detailed explanation-4: -Heart sounds are created from blood flowing through the heart chambers as the cardiac valves open and close during the cardiac cycle. Vibrations of these structures from the blood flow create audible sounds-the more turbulent the blood flow, the more vibrations that get created.