বহুনির্বাচনি (MCQ)
১. The first heart sound is mainly due to:
ক) Closure of the aortic and pulmonary valves
খ) Closure of the mitral and tricuspid valves
গ) Rapid ventricular filling
ঘ) Atrial contraction
ঙ) Opening of the AV valves
উত্তর দেখুন
সঠিক উত্তর: খ) Closure of the mitral and tricuspid valves
ব্যাখ্যা: S1 is produced by closure of the AV (mitral and tricuspid) valves at the start of ventricular systole. S2 is closure of the semilunar valves.
📖 রেফারেন্স: Guyton & Hall, Textbook of Medical Physiology · Heart valves and heart sounds