The interventricular septum is a thick wall of muscle that separates the left and right ventricles of the heart. This structure plays a crucial role in maintaining the heart's efficiency by preventing the mixing of oxygen-rich blood from the left ventricle with oxygen-poor blood from the right ventricle. Additionally, the interventricular septum contributes to the heart's electrical conduction system, which helps regulate heartbeats. It is essential for proper heart function, as any defects in this septum can lead to conditions such as ventricular septal defects, affecting overall cardiovascular health.