NURSING ANM AND GNM

Detailed explanation-1: -The sinus node continuously generates electrical impulses, thereby setting the normal rhythm and rate in a healthy heart. Hence, the SA node is referred to as the natural pacemaker of the heart.

Detailed explanation-2: -The heart’s intrinsic pacemaker, the sinoatrial node (SAN), generates spontaneous action potentials (AP) through a system of coupled oscillators whose common output initiates each normal heartbeat.

Detailed explanation-3: -The SA node is predominantly innervated by efferent branches of the right vagus nerves, although some innervation from the left vagus is often observed. Experimental denervation of the right vagus to the heart leads to an abrupt increase in SA nodal firing rate if the resting heart rate is below 100 beats/min.

Detailed explanation-4: -The SA node starts the sequence by causing the atrial muscles to contract. That’s why doctors sometimes call it the anatomical pacemaker. Next, the signal travels to the AV node, through the bundle of HIS, down the bundle branches, and through the Purkinje fibers, causing the ventricles to contract.