The heart is two pumps side by side. The right side pumps blood to the lungs; the left side pumps it to the whole body.
Four chambers
Two atria on top receive blood. Two ventricles below pump it out. The left ventricle has the thickest wall because it pumps against the highest pressure.
Four valves
Valves keep blood moving in one direction. The tricuspid and mitral valves sit between atria and ventricles; the pulmonic and aortic valves sit at the exits of the ventricles.
The path of blood
Body veins, right atrium, tricuspid valve, right ventricle, pulmonic valve, lungs, left atrium, mitral valve, left ventricle, aortic valve, aorta, body.
| Valve | Between | Listen at |
|---|---|---|
| Tricuspid | Right atrium and right ventricle | 4th left intercostal space, lower sternal border |
| Pulmonic | Right ventricle and pulmonary artery | 2nd left intercostal space |
| Mitral | Left atrium and left ventricle | 5th intercostal space, midclavicular line |
| Aortic | Left ventricle and aorta | 2nd right intercostal space |
At the bedside
Valves closing make the heart sounds: S1 when the mitral and tricuspid close, S2 when the aortic and pulmonic close. A leaking or narrow valve makes a murmur.
Related guides
Written by Making Synapses. Topic reference: OpenStax, Anatomy and Physiology 2e (no text adapted).