Question

Anatomy of the Heart 389 Right- ventricle - att ventricle Interventricular septum Entrance of inferior vena cava Cu surface ol wall pt night ventricie Fossa ovalis Peg in opening of coronary sinus Cusp of pulmonary valve Chordae tendineae Papillary Cusp of tricuspid valve muscle Wall of right ventricle (reflected) Moderator band Heart apex Figure 23.7 Right side of the sheep heart opened and reflected to reveal internal structures. Overview diagram illustrates the anatomical differences between the right and left ventricles. The left ventricle has thicker walls, and its cavity is basically circular. By contrast, the right ventricle cavity is crescent-shaped and wraps around the left ventricle. septum to anterior papillary muscles. It contains a branch of the atrioventricular bundle and helps coordinate contraction of the ventricle. 14. Make a longitudinal incision through the left atrium, and continue it into the left ventricle. Notice how much thicker the myocardium of the left ventricle is than that of the right ven- tricle. Measure the thickness of the left and right ventricular walls in millimeters, and record the numbers: left 11. Reflect the cut edges of the superior vena cava, right atrium, and right ventricle to obtain the view seen in Figure 23.7. Observe the comblike ridges of muscle through out most of the right atrium. This is called pectinate muscle (pectin means "comb"). Identify, on the posterior atrial wall, the large opening of the inferior vena cava, and follow it to its external opening with a probe. Notice that the atrial walls in the vicinity of the venae cavae are smooth and lack the roughened appearance (pectinate musculature) of the other regions of the atrial walls. Just below the inferior vena caval opening, identify the opening of the coronary sinus. Nearby, locate an oval depression, the fossa ovalis, in the interatrial seplum. This depression marks the site of an open- ing in the fetal heart, the foramen ovale, which allows blood to pass from the right to the left atrium, thus bypassing the fetal lungs. 12. Identify the papillary muscles in the right ventricle, and follow their attached chordae tendineae to the cusps of the tricuspid valve. Notice the pitted and ridged appearance (trabeculae carneae) of the inner ventricular muscle. 13. Identify the moderator band (septomarginal band), a bundle of cardiac muscle fibers connecting the interventricular right Compare the shape of the left ventricular cavity to the shape of the right ventricular cavity (see the overview diagram in Figure 23.7).

Answer 1

thickness:RIGHT=4MM (3-5MM),LEFT=10MM (9-14MM)

SHAPE OF CAVITY:RIGHT=CRESCENTIC,LEFT=CIRCULAR

PAPPILARY MUSCLE AND CHORDAE TENDINAE PRESENT IN BOTH VENTRICLES.

MITRAL VALVE HAS 2 CUSPS HENCE CALLED BICUSPID VALVE ASLO WHEREAS TRICUSPID VALVE HAS 3 CUSPS PRESENT.

The human aortic valve has less muscular support than sheep aortic valves but has a larger diameter compared to sheep valve. The diameter of the sheep aortic valve is smaller than in humans.