Sinoatrial node (Sa node Located in the right artium Fire off action potentials at a regular and intrinsic rate Both parasympathetic and sympathetic neural input can modulate its pacemaker activity, or automaticity The existence of discrete conducting pathways in the atria is still disputed. The signal arrives to th left atrium and atrioventricular node(av node)Sinoatrial node (SA node) • Located in the right artium. • Fire off action potentials at a regular and intrinsic rate. • Both parasympathetic and sympathetic neural input can modulate its pacemaker activity, or automaticity. • The existence of discrete conducting pathways in the atria is still disputed. The signal arrives to the left atrium and atrioventricular node (AV node). 13