Think of it like clapping your hands: the sound isn't from the movement itself, but from the instant two surfaces meet. In the heart, that meeting is the forceful closure of valves designed to keep blood flowing in one direction.
: Closing these valves prevents blood from flowing backward into the upper chambers (atria).
| Sound | Other Name | What Closes | When it Happens | | :--- | :--- | :--- | :--- | | | S1 | Mitral & Tricuspid valves | Start of contraction (systole) | | Dub | S2 | Aortic & Pulmonary valves | Start of relaxation (diastole) |
The "dub" is the second heart sound (S2) and occurs at the end of ventricular systole or the beginning of , when the heart relaxes. How the Heart Works - How the Heart Beats | NHLBI, NIH
Why Does The Heart Make A Lub Dub Sound !!install!! Jun 2026
Think of it like clapping your hands: the sound isn't from the movement itself, but from the instant two surfaces meet. In the heart, that meeting is the forceful closure of valves designed to keep blood flowing in one direction.
: Closing these valves prevents blood from flowing backward into the upper chambers (atria). why does the heart make a lub dub sound
| Sound | Other Name | What Closes | When it Happens | | :--- | :--- | :--- | :--- | | | S1 | Mitral & Tricuspid valves | Start of contraction (systole) | | Dub | S2 | Aortic & Pulmonary valves | Start of relaxation (diastole) | Think of it like clapping your hands: the
The "dub" is the second heart sound (S2) and occurs at the end of ventricular systole or the beginning of , when the heart relaxes. How the Heart Works - How the Heart Beats | NHLBI, NIH | Sound | Other Name | What Closes