Final answer:
No, the normal heart sounds ("lub-dub") are not associated with the opening of valves but rather their closing during different phases of the heartbeat, specifically S1 with atrioventricular valve closure and S2 with semilunar valve closure.
Step-by-step explanation:
The normal heart sounds that occur as valves open and close, and the heart chambers fill and empty of blood, are normally S1 and S2. S1, the "lub" sound, is caused by the closing of the atrioventricular valves during ventricular contraction. The "dub" sound, known as S2, occurs when the semilunar valves close during ventricular diastole. These sounds are associated with the normal function of the heart as it pumps blood through the body. Additional heart sounds like S3 and S4 may indicate abnormal cardiac conditions.