ANATOMY

Detailed explanation-1: -Sinoatrial node It sends the electrical impulses that start the heartbeat. The SA node is in the upper part of your heart’s right atrium.

Detailed explanation-2: -The sinus node is sometimes called the heart’s “natural pacemaker.” Each time the sinus node generates a new electrical impulse; that impulse spreads out through the heart’s upper chambers, called the right atrium and the left atrium (figure 2).

Detailed explanation-3: -The SA (sinoatrial) node generates an electrical signal that causes the upper heart chambers (atria) to contract. The signal then passes through the AV (atrioventricular) node to the lower heart chambers (ventricles), causing them to contract, or pump. The SA node is considered the pacemaker of the heart.

Detailed explanation-4: -The SA (sinus) node represents a cluster of myocytes with pacemaker activity. Under normal circumstances, it generates electrical impulses that set the rhythm and rate of the heart. The mass of the sinus node is too small to create a substantial electrical signal that can be detected on the electrocardiogram (ECG).