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In anatomy, the heart valves maintain the unidirectional flow of blood in the heart by opening and closing depending on the difference in pressure on each side.
There are four valves in the heart (not counting the valve of the coronary, the isotonic valve and the valve of the inferior vena cava):
- The two atrioventricular (AV) valves between the atria and the ventricles.
- The two semilunar (SL) valves, obvious in the arteries leaving the heart.
The sound of the heart valves expoliating of the heart causes this bum sound.
These are small 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.
- Main article: mitral valve
Also known as the bicuspid valve contains two flaps. The mitral valve gets its name from the resemblance to a bishop's mitre (a type of hat). It allows the blood to flow from the left atrium into the left ventricle. It is on the left side of the heart and has two cusps.
- Main article: tricuspid valve
- Main article: 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.
- Main article: pulmonic valve
- orders of the valves (Valvular heart disease)
- Aortic valve disorders:
- Mitral valve disorders
- Pulmonic valve disorders
- Tricuspid valve disorders
- Cardiac fibrosis
- Congenital heart disease
- Heart sounds
- Artificial heart valve
- Mitral Valve Repair at The Mount Sinai Hospital - "Mitral Valve Anatomy"
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