What is meant by origin of …

Heart beat is the rhythmic contraction and relaxation of the heart. Each heart beat includes one systole (contraction phase) and one diastole (relaxation phase) of the heart to distribute and receive blood to and from the body. The heart of a healthy person beats 72 times per minute. Origin of heart beat. The mammalian heart is myogenic (myo = muscle, genic = originating from). It means the heart beat originates from a muscle, (however, it is regulated by the nerves). The heart beat originates from the sinoatrial node (SANode)—pace maker, which lies in the wall of the right atrium, near the opening of the superior vena cava. The SA node is a mass of neuromuscular tissue.

Conduction of heart beat. Another mass of neuromuscular tissue, the atrio-venticular node (AV node) is situated in the wall of the right atrium. The AV node picks up the wave of contraction propagated by SAnode. Amass of specialized fibres, the bundle of His, originates from the AV node. The bundle of His divides into two branches, one going to each ventricle. Within the myocardium of the ventricles the branches of bundle of His divide into a net work of fine fibres called the Purkinje fibres. The bundle of His and the Purkinje fibres convey impulse of contraction from the AV node of the myocardium of the ventricles.