The Human Heart Location - center of the chest, below the sternum - enclosed in tough double walled pericardium (allows the heart to move and protects it from friction)

Structure and Blood Flow - double pump with two, two chambered halves, separated by the septum 1) Right Atrium - receives blood from the upper part of the body (superior vena cava) and lower part of the body (inferior vena cava). - contraction pushes blood through the right A-V valve (tricuspid valve) - all of the valves in the heart are one-way valves

2) Right Ventricle - receives blood from the right atrium - strong muscular contraction pushes blood through the right S-L valve (pulmonary valve) through the pulmonary artery towards the lungs

3) Pulmonary Artery - splits into right and left and takes the blood away from the heart to the lungs for oxygenation and the removal of carbon dioxide

4) Pulmonary Vein - right and left bring blood from the lungs to the left atrium - left atrium contracts (simultaneously with right atrium) and sends blood through the left A-V valve (mitral valve).

5) Left Ventricle - receives blood from left atrium - strong muscular contraction (simultaneous with right ventricle) pushes blood through the S-L valve of the aorta (aortic valve) - coronary, brachiocephalic, left carotid, left subclavian arteries branch away before the loop down

Heart Chambers Chamber Location Function Left Atrium Top Left Receives blood from the lungs Right Atrium Top Right Receives blood from the entire body Left Ventricle Bottom Left Sends blood to the entire body Right Ventricle Bottom Right Sends blood directly to the lungs

Blue = Deoxygenated Blood Red = Oxygenated Blood http://www.youtube.com/watch?v=rguztY8aqpk