Heart valve

Heart valve

In anatomy, the heart valves are valves in the heart that maintain the unidirectional flow of blood by opening and closing depending on the difference in pressure on each side. The mechanical equivalent of the heart valves would be the reed valves which is another type of valve.

There are four valves of the heart (not counting the valve of the coronary sinus and valve of the inferior vena cava):
* The two "atrioventricular (AV) valves" ensure blood flows from the atria to the ventricles, and not the other way.
* The two "semilunar (SL) valves" are present in the arteries leaving the heart, and they prevent blood flowing back from the arteries into the ventricles.

The sound of the heart valves shutting causes the heart sounds.

Atrioventricular valves

These are small, single cuspid valves that prevent backflow from the ventricles into the atria during systole. They are anchored to the wall of the ventricle by chordae tendineae, that prevent the valve from inverting.

The chordae tendineae are attached to papillary muscles that cause tension to better hold the valve. Together, the papillary muscles and the chordae tendinae are known as the subvalvular apparatus. The function of the subvalvular apparatus is to keep the valves from prolapsing into the atria when they close. The subvalvular apparatus have no effect on the opening and closure of the valves, however. This is caused entirely by the pressure gradient across the valve.

Mitral valve

Also known as the "bicuspid valve", the mitral valve gets its name from the resemblance to a bishop's mitre (a type of hat). It prevents blood flowing from the left ventricle into the left atrium. It is on the left side of the heart and has two cusps.

A common complication of rheumatic fever is thickening and stenosis of the mitral valve.

Tricuspid valve

The tricuspid valve is on the right side of the heart, between the right atrium and the right ventricle which stops the backflow of blood between the two.

emilunar valves

These are positioned on the pulmonary artery and the aorta. These valves do not have chordae tendinae, but are more similar to valves in veins.

Aortic valve

The aortic valve lies between the left ventricle and the aorta. The aortic valve has three cusps. During ventricular systole, pressure rises in the left ventricle. When the pressure in the left ventricle rises above the pressure in the aorta, the aortic valve opens, allowing blood to exit the left ventricle into the aorta. When ventricular systole ends, pressure in the left ventricle rapidly drops. When the pressure in the left ventricle decreases, the aortic pressure forces the aortic valve to close. The closure of the aortic valve contributes the A2 component of the second heart sound (S2).

The most common congenital abnormality of the heart is the bicuspid aortic valve. In this condition, instead of three cusps, the aortic valve has two cusps. This condition is often undiagnosed until the person develops calcific aortic stenosis. Aortic stenosis occurs in this condition usually in patients in their 40s or 50s, an average of over 10 years earlier than in people with normal aortic valves.

Pulmonic valve

The pulmonic valve lies between the right ventricle and the pulmonary artery and also has three cusps.

ee also

* Disorders of the valves (Valvular heart disease)
** Aortic valve disorders:
*** Aortic insufficiency
*** Aortic stenosis
*** Aortic valve replacement
*** Aortic valve repair
*** Aortic valvuloplasty
** Mitral valve disorders
*** Mitral valve prolapse
*** Mitral regurgitation
*** Mitral stenosis
*** Mitral valve replacement
*** Mitral valve repair
*** Mitral valvuloplasty
** Pulmonic valve disorders
** Tricuspid valve disorders
* Cardiac fibrosis
* Congenital heart disease
* Endocarditis
* Heart sounds
*Artificial heart valve

External links

* [http://www.mitralvalverepair.org/content/view/51/ Mitral Valve Repair at The Mount Sinai Hospital] - "Mitral Valve Anatomy"

Wikimedia Foundation. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • heart valve — n any of the valves that control blood flow to and from the heart and that include the atrioventricular valves, the aortic valve, and the pulmonary valve called also cardiac valve …   Medical dictionary

  • Heart valve repair — Intervention ICD 9 CM 35.0 35.2 Heart valve repair is a surgical technique used to fix defects in …   Wikipedia

  • Heart valve dysplasia — is a congenital heart defect which affects the aortic, pulmonary, mitral, and tricuspid heart valves. Pulmonary valve stenosis and aortic valve stenosis are discussed separately. Dysplasia of the mitral and tricuspid valves can cause leakage of… …   Wikipedia

  • Heart valve stenosis — can refer to one of the following conditions: * Mitral stenosis * Aortic valve stenosis …   Wikipedia

  • heart valve prosthesis — prosthetic heart valve; see under valve …   Medical dictionary

  • heart valve — noun 1. a valve to control one way flow of blood • Syn: ↑cardiac valve • Hypernyms: ↑valve • Hyponyms: ↑atrioventricular valve, ↑semilunar valve • Part Holonyms: ↑ …   Useful english dictionary

  • heart valve — noun The valves in heart which prevent blood from moving wrong direction …   Wiktionary

  • heart valve — membrane that controls the flow of blood in and out of the heart …   English contemporary dictionary

  • Artificial heart valve — An artificial heart valve is a device implanted in the heart of a patient with heart valvular disease. When one of the four heart valves malfunctions, the medical choice may be to replace the natural valve with an artificial valve. This requires… …   Wikipedia

  • Valve of coronary sinus — Valve of the coronary sinus Interior of right side of heart. (Valve of the coronary sinus labeled at bottom left.) Latin valvula sinus coronarii Gray s …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”