The second heart sound is associated with the closure of which valves, and has two components: first is closure of the aortic valve and second is closure of the pulmonic valve.

The second heart sound is associated with the closure of which valves, and has two components: first is closure of the aortic valve and second is closure of the pulmonic valve.

• A. S1 heart sound
• B. S2 heart sound
• C. S3 heart sound
• D. S4 heart sound

Answer: (B)

The second heart sound comes from the closing of the semilunar valves at the end of systole. It has two components: the first component is the closure of the aortic valve (A2) and the second component is the closure of the pulmonic valve (P2). In most people A2 is heard a moment before P2, which can split into two sounds during inspiration as P2 is delayed slightly with increased venous return; this is normal physiological splitting. S2 is distinct from S1, which comes from the closure of the atrioventricular valves at the start of systole, and from S3/S4, which are extra sounds related to rapid filling or stiff ventricular walls. So the described two-component sound corresponds to the second heart sound.

The second heart sound comes from the closing of the semilunar valves at the end of systole. It has two components: the first component is the closure of the aortic valve (A2) and the second component is the closure of the pulmonic valve (P2). In most people A2 is heard a moment before P2, which can split into two sounds during inspiration as P2 is delayed slightly with increased venous return; this is normal physiological splitting. S2 is distinct from S1, which comes from the closure of the atrioventricular valves at the start of systole, and from S3/S4, which are extra sounds related to rapid filling or stiff ventricular walls. So the described two-component sound corresponds to the second heart sound.