1. Structures of the Heart

2. Chambers Your heart is divided into 4 chambers: Right and Left Atria Right and Left Ventricles

3. Right Atrium Receives de-oxygenated blood from superior vena cava (head and upper body) and inferior vena cava (legs and lower torso). Contains pacemaker cells in a place called the sinoatrial node----This node sends electrical signals to the right atrium causing it to contract pushing blood to right ventricle.

4. Right Ventricle Receives de-oxygenated blood from right atrium----Once filled it pumps blood into pulmonary artery. Receives electrical signal from group of pacemaker cells located in the atrioventricular node causing it to contract.

5. Left Atrium Receives oxygenated blood from lungs through the pulmonary veins. Once filled it contracts due to electrical signal from the sinoatrial node.

6. Left Ventricle Receives oxygenated blood from left atrium----Once filled it pumps blood into aorta and out to the rest of the body. Receives electrical signal from group of pacemaker cells located in the atrioventricular node causing it to contract.