Describe the conducting system of human heart.

Explanation

(a) Human heart is myogenic . The heart beat originates in modified cardic muscles called sinoatrial node (SA node) which lies in the wall of right atrium near the opening of superior vena cava .
(b) The SA node is called pace maker because it has power of regeneration of wave of contraction . The wave fo contractions of cardiac impulse generated by SA node is condcted by cardiac muscle fibres to both atria causing their contraction .
(c) The AV node ( Atrio - ventricular ) is located in the wall of right atrium near opening of coronary Sinus which receives the waveof contraction generated bu SA node through internodal pathways .
(d) Bundle of His : It arises from AV node and divides into right and left bundle branches located in interventricular septum .
(e) The bundle branches give rise to purkinje fibres which penetrate into myocardium of ventricles .
(f) Bundle of His and purkinje fibres conduct the wave of contraction from AV node to myocardium of ventricles causing their contraction .