Pacemaker Cells. Cardiac pacemaker cells are mostly found in the sinoatrial (SA) node, which is situated in the upper part of the wall of the right atrium. These cells have natural automaticity, meaning they can generate impulses themselves.
The autorhythmic cells are located in these areas: Sinoatrial (SA), or sinus, node. Atrioventricular (AV) node. Atrioventricular (AV) bundle (also sometimes called the bundle of His)
The outside only looks pigmented because of the color reflecting off it, but the inside is white and unpigmented because it is reflecting all the colors. Does this help?