Final answer:
In a healthy heart, there are two audible heart sounds: S1 and S2. Additional heart sounds like S3 and S4 may indicate cardiac problems. S3 may be heard in certain individuals, but if heard later in life, it could indicate congestive heart failure. S4 occurs prior to S1 and may indicate left ventricular failure.
Step-by-step explanation:
In a normal, healthy heart, there are only two audible heart sounds: S1 and S2. S1 is the sound created by the closing of the atrioventricular valves during ventricular contraction and is described as a "lub," or first heart sound. The second heart sound, S2, is the sound of the closing of the semilunar valves during ventricular diastole and is described as a "dub."
Additional heart sounds like S3 and S4 are not normally heard in healthy individuals. However, if these sounds are present, it could indicate certain cardiac problems. S3 may be heard in youth, some athletes, and pregnant women, but if it is heard later in life, it may indicate congestive heart failure. S4 occurs prior to S1 and may indicate left ventricular failure.