In the human body, the 'Sinoatrial (SA) node' is located in the wall of the: MCQ with Answer and Explanation

The Sinoatrial (SA) node, the natural pacemaker of the heart, is a small, specialized mass of autorhythmic cardiac muscle cells located in the upper wall of the right atrium, just below the opening of the superior vena cava. It spontaneously generates electrical impulses at a regular rate, which spread through the atrial myocardium, causing the atria to contract and push blood into the ventricles. The impulse then reaches the AV node.