The sinus node—the part of the heart's electrical system that generates the heartbeat signal—is located within the walls of the right atrium. The right atrium sits at the top right side of the ...

The atria (plural of atrium) are where the blood collects when it enters the heart. The ventricles pump the blood out of the heart to the lungs or around the body. The septum separates the right ...

The atria (plural of atrium) are where the blood collects when it enters the heart. The ventricles pump the blood out of the heart to the lungs or around the body. The septum separates the right ...