Chordae tendineae

From Wikipedia, the free encyclopedia

This article needs additional citations for verification. Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (February 2008)

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.

Contents 1 Mechanism 2 See also 3 Reference 4 External links

[edit] 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]

[edit] See also

• Cardiac cycle

[edit] Reference

[edit] 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

v • d • e Anatomy of torso, cardiovascular system: heart (TA A12.1, GA 5.524) General Surface base · apex · grooves (coronary/atrioventricular, interatrial, anterior interventricula, posterior interventricular) · surfaces (sternocostal, diaphragmatic) · borders (right, left) · Openings of smallest cardiac veins Internal atria (interatrial septum, musculi pectinati, sulcus terminalis) · ventricles (interventricular septum, trabeculae carneae, chordae tendineae, papillary muscle) · valves · cusps · Atrioventricular septum cardiac skeleton (fibrous trigone, fibrous rings) Intervenous tubercle Chambers Right heart (vena cavae, coronary sinus) → right atrium (atrial appendage, fossa ovalis, limbus of fossa ovalis, crista terminalis, valve of inferior vena cava, valve of coronary sinus) → tricuspid valve → right ventricle (conus arteriosus, moderator band/septomarginal trabecula)  → pulmonary valve → (pulmonary artery and pulmonary circulation) Left heart (pulmonary veins) → left atrium (atrial appendage) → mitral valve → left ventricle → aortic valve (aortic sinus) → (aorta and systemic circulation) Layers Endocardium Heart valves Myocardium Conduction system: Cardiac pacemaker · SA node · AV node · bundle of His · Purkinje fibers Pericardial cavity Pericardial sinus Pericardium fibrous pericardium (Sternopericardiac ligaments) · serous pericardium (epicardium/visceral layer) · Fold of the left vena cava heart navs: anat/physio/dev, noncongen/congen/neoplasia, symptoms+signs/eponymous, proc