Contribution to the study of connective fibers in human mitral valve

8 hearts of male and female, white and non-white Brazilians of different ages were studied. The histological arrangement of the collagen and elastic tissue of the leaflets of the left atrioventricular valve was studied. The histological study of the leaflets under polarized light, showed that the collagen from the chordae tendineae fans out in its interior and reaches a fibrous ring from the valve. Specific staining for elastic fibers revealed that these fibers are chiefly concentrated on the free margin of the leaflets. These findings were discussed based on the physiology of the papillary muscle contraction and on the proposed mechanisms of the valve closure.