Question

The given diagram represents a section of the human heart. Answer the questions that follows.

What causes the heart sounds ‘Lubb’ and ‘Dupp’.

Answer 1

• The rhythmic noises accompanying heartbeat are called heart sounds.
• The heart sounds consist mainly of two separate noises occurring when the two sets of heart valves close.
• Normally, two distinct sounds are heard through the stethoscope: a low, slightly prolonged “lub” occurring at the beginning of ventricular contraction, or systole, and produced by closure of the bicuspid and tricuspid valves, and a sharper, higher-pitched “dup”, caused by closure of aortic and pulmonary valves at the end of systole.