What do you mean by bundle of His and Purkinje fibres?
Bundle of His is the main conduction fiber group reaching the ventricles from the atrioventricular node. It divides into right and left bundle branches. Left bundle further divide into two fascicles (anterior and posterior). These bundle branches further divide into tiny branches which connect with the heart muscles. These tiny branches of the conduction system which connect with the heart muscle fibres are known as Purkinje fibres. Conduction is faster in the larger Bundle of His than in the tiny Purkinje fibres. Purkinje fibres are the final common pathway for the controlling impulses from the sinoatrial node to the heart muscle cells to maintain regular contraction.