question_answer 23)

The cardiac impulse is initiated and conducted further up to ventricle. The correct sequence of conduction of impulse is

(a)	SA Node	AV Node	Purkinje fiber	AV Bundle
(b)	SA Node	Purkinje fiber	AV Node	AV Bundle
(c)	SA Node	AV Node	AV Bundle	Purkinje fiber
(d)	SA Node	Purkinje fiber	AV Bundle	AV Node

Answer:

                  SA Node It is situated in the walls of the right auricle near the opening of the superior vena cava. In myogenic heart the contraction is initiated by SA node. AV Node The wave of contraction reaches AV node which is stimulated to emit an impulse of contraction spreading to the ventricular muscle via the atrio ventricular bundle and then to the Purkinje fibres stimulating heart beat.