Chordae tendineae

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Chordae tendineae
Interior of right side of heart.
The chordae tendineae are the unlabled, white tendons seen connecting the valves to the heart muscle
Latin	chordae tendineae cordis
Gray's	subject #138 532
MeSH	Chordae+Tendineae

The chordae tendineae, or heart strings, are cord-like tendons that connect the papillary muscles to 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.

Mechanism

During atrial systole, blood flows from the atria to ventricles down the pressure gradient. Chordae tendineae are relaxed because the atrioventricular valves are forced open.^[1]

When the ventricles of the heart contract in ventricular systole, the increased blood pressures in both chambers push the tricuspid valve and mitral valve 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 the eversion by becoming tense thus pulling the flaps, holding them in closed position.^[1]

See also

• Cardiac cycle

Reference

External links

• SUNY Labs 20:st-0701 cvfg
• chordae+tendonea+of+heart at eMedicine Dictionary
• false+chordae+tendonea at eMedicine Dictionary
• Organology at UC Davis Circulatory/heart/chambers0/chambers11 - "Mammal heart, chambers (Gross, Low)"
• Bioweb at UWLAX Human heart model (bicuspid valve)
• Illustration at health-pictures.com