PATHOLOGY

Detailed explanation-1: -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 closure of semilunar valves produces the heart sound “dub”. This occurs at the end of ventricular systole.

Detailed explanation-3: -The ‘lub’ is the first heart sound, commonly termed as S1 and is caused by the turbulence caused by the closure of the mitral (or bicuspid) and tricuspid valves at the start of systole. The second sound ‘dub’ or S2 is caused by the closure of aortic and pulmonic (Semi-lunar) valves, marking the end of systole.

Detailed explanation-4: -The first heart sound (“lub”) represents the closure of the mitral and tricuspid valves in early ventricular systole. You are mostly hearing the closure the mitral valve. It can be heard the loudest at the mitral area at the apex.