ANATOMY

Detailed explanation-1: -The SA node, also known as the sinus node, represents a crescent-like shaped cluster of myocytes divided by connective tissue, spreading over a few square millimeters. It is located at the junction of the crista terminalis in the upper wall of the right atrium and the opening of the superior vena cava.

Detailed explanation-2: -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-3: -The sinoatrial node (SA node) is a specialized myocardial structure that initiates the electrical impulses to stimulate contraction, and is found in the atrial wall at the junction of superior caval vein and the right atrium (Mikawa and Hurtado, 2007).

Detailed explanation-4: -The CS arises in the SA node, which is found in the upper anterior right atrium (Figure 1).

Detailed explanation-5: -The SA node called the sinoatrial node lies in the wall of the right atrium near the opening of the superior vena cava. Q. Assertion :The SA node acts as pacemaker Reason: The SA node is located in the wall of the right atrium near the interatrial septum.