Which structure separates the left and right sides of the heart?

The septum is the structure that separates the left and right sides of the heart, playing a crucial role in maintaining the separation of oxygenated and deoxygenated blood. The heart has two main septa: the interatrial septum separates the left and right atria, while the interventricular septum separates the left and right ventricles. This division is essential for efficient circulation, as it prevents the mixing of oxygen-rich blood from the left side of the heart with oxygen-poor blood from the right side.

The myocardium, which is the heart muscle itself, is involved in the contraction of the heart to pump blood but does not provide separation between the sides. Similarly, valves function to ensure unidirectional blood flow within the heart and prevent backflow, but they do not separate the heart chambers. The endocardium is the inner lining of the heart chambers but also does not serve the purpose of separating the left and right sides.

Understanding the function of the septum is fundamental for grasping the overall anatomy and function of the heart in the context of cardiovascular physiology.