Light and Ultrastructural Study of the Chordae Tendineae in the Heart of the Ostrich (Struthio camelus)

The chordae tendineae of the heart are collagenous strands which extend from the apical margin of papillary muscles of the heart to the various areas on the ventricular surface of the valve leaflets. They convey the contraction of the papillary muscles to the valve and so prevent the latter’s eversion. Eight hearts of the ostrich were collected, opened the left side of the heart and the length of the chordae tendineae were measured. Macroscopically they had interconnection and attached directly to the free edge of the left atrioventricular valve or tricuspid. Routine paraffin sectioning with special staining method and transmission electron microscopy method was done. Our results manifested that the chordae tendineae basically was connective tissue and covered by endocardium. The core connective tissue of chordae tendineae in the proximal part was loose connective tissue and in distal parts was dense irregular connective tissue whereas in the middle part it was dense regular connective tissue.