PATHOLOGY

Detailed explanation-1: -Electrical impulses from the heart muscle cause your heart to beat (contract). This electrical signal begins in the sinoatrial (SA) node, located at the top of the heart’s upper-right chamber (the right atrium). The SA node is sometimes called the heart’s “natural pacemaker.”

Detailed explanation-2: -Structure. The sinuatrial node is found in the posterolateral wall of the sinus of venae cavae in the right atrium (hence ‘sinu-’ + atrial) close to the junction of the superior vena cava with the right atrium, deep to the crista terminalis.

Detailed explanation-3: -The sino-atrial (SA) node is a specialised bundle of neurons located in the upper part of the right atrium of the heart. The cardiac impulse originating from the SA node triggers a sequence of electrical events in the heart, thereby controlling the sequence of muscle contraction that pumps blood out of the heart.