Heart valve

In anatomy, the heart valves are valves in the heart that prevent blood from flowing the wrong way.

Semilunar 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.

Related Topics:
Pulmonary artery - Aorta

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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).

Related Topics:
Left ventricle - Aorta - Systole - Heart sound

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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 10 years earlier than in people with normal aortic valves.

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Pulmonic valve

The pulmonic valve lies between the right ventricle and the pulmonary artery and also has three cusps. Similar to the aortic valve, the pulmonic valve opens in ventricular systole, when the pressure in the right ventricle rises above the pressure in the pulmonary artery. At the end of ventricular systole, when the pressure in the right ventricle falls rapidly, the pressure in the pulmonary artery will close the pulmonic valve.

Related Topics:
Right ventricle - Pulmonary artery

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The closure of the pulmonic valve contributes the P2 component of the second heart sound (S2). The right heart is a low pressure system, so the P2 component of the second heart sound is usually softer than the A2 component of the second heart sound. However, it is physiologic to hear both components separated only by some young people during inspiration.

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