The Term, ‘Heart Strings’ Isn’t Just For Love Songs.
It turns out that we’ve all got Heart Strings, diligently strumming along inside our chests…and not the kind you hear about in poetry and song lyrics.
The Chordae Tendineae (tendinous chords), or heart strings, are cord-like tendons that connect the papillary muscles to the outer edges of the Tricuspid Valve and the Mitral Valve in the heart. Chordae tendineae are approximately 80% collagen, while the remaining 20% is made up of elastin and endothelial cells.
During atrial systole (contraction of the atria), blood flows from the atria to the ventricles down the pressure gradient. The chordae tendineae are relaxed because the atrioventricular valves are forced open.
When the ventricles of the heart contract in ventricular systole, the increased blood pressures in both chambers push the AV valves to close simultaneously, preventing backflow of blood into the atria. Since the blood pressure in atria is much lower than that in the ventricles, the flaps attempt to evert to the low pressure regions. The chordae tendineae prevent this eversion by becoming tense thus pulling the flaps, holding them in closed position.
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