Choose the number of correct statements w.r.t diagram shown. The entire heart is made of cardiac muscles. The walls of atria are much thicker than that of the ventricles. A specialised cardiac musculature called the nodal tissue is not distributed in the heart. The valves prevent any backward flow.

Step-by-step solution

The opening between the right atrium and the right ventricle is guarded by a valve formed of three muscular flaps or cusps, the tricuspid valve, whereas a bicuspid or mitral valve guards the opening between the left atrium and the left ventricle. The openings of the right and the left ventricles into the pulmonary artery and the aorta respectively are provided with the semilunar valves. The valves in the heart allows the flow of blood only in one direction, i.e., from the atria to the ventricles and from the ventri