SPATIAL ARRANGEMENT OF THE HEART-MUSCLE FASCICLES AND INTRAMYOCARDIALCONNECTIVE-TISSUE IN THE SPANISH FIGHTING BULL (BOS-TAURUS)

The spatial arrangement of the muscle fascicles and intramyocardial co nnective tissue was examined in the ventricles of the heart of the Spa nish fighting bull (Bos taurus). In both ventricles, the muscle fascic les of the myocardium are arranged in 3 main directions, forming 3 mus cle layers within the ventricular wall. The preferentially vertical ar rangement of the muscle fascicles in the superficial and deep layers a t the level of the fibrous aortic rings and the base of the semilunar valve leaflets suggests that these fascicles are actively involved in valvular dynamics. After controlled digestion of myocytes and elastic fibres with NaOH, a 3-dimensional arrangement of the scaffolding of co nnective tissue that supports the muscle fascicles and myocytes was ob served. The arrangement and structure of this scaffolding may influenc e the order of contraction of muscle fascicles in different layers of the ventricle. In addition, differences were observed between the conn ective tissue scaffolding surrounding the myocytes of the 2 ventricles ; these variations were correlated with the different biomechanical pr operties.