The human heart has four chambers: two atria (right and left) and two ventricles (right and left). This chambered structure allows for the separation of oxygenated and deoxygenated blood, ensuring efficient blood circulation through the pulmonary and systemic circuits. In cardiac surgeries, such as valve replacements or septal defect repairs, understanding the specific chamber anatomy is crucial for accurate intervention and avoiding complications. The four-chambered design is fundamental for maintaining unidirectional blood flow and proper cardiac function.

Reference: Gray's Anatomy, Henry Gray, 42nd Edition.