What structure divides the heart into two halves?

The structure that divides the heart into two halves is the septum. The septum is a muscular wall that separates the left and right sides of the heart, consisting of the interatrial septum, which separates the atria, and the interventricular septum, which separates the ventricles. This division is crucial for maintaining a two-circuit system in the circulatory system—one for oxygenated blood to the body and one for deoxygenated blood to the lungs. By keeping the oxygen-rich blood and oxygen-poor blood separate, the septum plays an essential role in the efficient functioning of the heart, ensuring that the circulatory system operates effectively and that oxygenation of blood is maximized.