His, bundle of

His, bundle of

a group of special cardiac muscle fibres that runs from the atrioventricular node down to the septum between the ventricles and, with the Purkinje fibres, transmits electrical energy over the ventricular walls causing ventricular systole. See HEART and HEART, CARDIAC CYCLE.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005