| left atrioventricular valve | <anatomy, cardiology> The heart valve that divides the left atrium and left ventricle. During left atrial contraction, the mitral valve opens to allow blood to flow into the left ventricle. Upon closure, the mitral valve prohibits the regurgitation of blood back into the left atrium. The mitral valve is the only heart valve that has only 2 valve cusps (all others have 3). (13 Nov 1997) |
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| lunula of semilunar valve | The free border of a semilunar valve at each side of the nodulus valvulae semilunaris. Synonym: lunula valvulae semilunaris. (05 Mar 2000) |