When listening to the heart, the "lub" is the valves snapping shut and the "dup" sound occurs when the valves close at the end of systole?

atrioventricular , semilunar  - When listening to the heart,  the examiner listens for the unique lup-dup sounds of the heart to understand if the heart is healthy. These sounds are generated when the heart beats to allow blood to  flow throughout the body. The sound is basically created each time  the heart valves snap shut. The "lub" is the atrioventricular valves snapping shut and the "dup" sound occurs when the semilunar valves close at the end of systole.

Habit is no concious

Joke: i thought it said drake and josh at first answer: probably unsure about this law. depending on how long the time is.