The two upper chambers are atria; the lower chambers are ventricles. Atria receive blood. Ventricles pump it out. Valves keep blood moving in one direction. In a front-view diagram, the body’s right side appears on your left.
Use the chamber map above to identify the same chambers in this simplified section. The dividing wall separates the two sides; the left ventricular wall is thicker.
Body → vena cava → right atrium → right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium → left ventricle → aorta → body. Blood passes through the heart twice on a complete circuit.
| Right side | Left side |
|---|---|
| Pumps blood to the lungs | Pumps blood to the rest of the body |
| Receives blood low in oxygen | Receives oxygenated blood from lungs |
| Shorter trip, lower pressure | Thicker ventricular muscle generates higher pressure |
The left ventricle needs a thicker muscular wall because it pumps blood around the whole body. The dividing wall separates oxygenated and deoxygenated blood. Red and blue show oxygen content in our diagrams; blood is never actually blue.
Coronary arteries supply the heart muscle with oxygen and glucose for respiration. A group of cells in the right atrium acts as the natural pacemaker. Artificial pacemakers use electrical impulses to help correct an irregular heart rhythm.
Right heart → lungs. Left heart → body. Valves prevent backflow; coronary arteries supply heart muscle.
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