What is the name of the muscular wall that separates the left and right sides of the heart?

The muscular wall that separates the left and right sides of the heart is known as the septum. The septum is crucial to the heart's function as it divides the heart into two halves, preventing the mixing of oxygenated blood in the left side with deoxygenated blood in the right side. This separation is vital for efficient circulation, allowing the heart to pump oxygen-rich blood to the body and return oxygen-poor blood to the lungs for oxygenation.

The aorta, on the other hand, is a major artery that carries blood away from the heart to the rest of the body, but it does not play a role in separating the heart's chambers. The ventricles are the two lower chambers of the heart that are responsible for pumping blood out of the heart, while auricles, or atria, are the upper chambers that receive blood. Neither the ventricles nor the auricles serve as a dividing wall. Therefore, the septum is the correct term for the structure that separates the left and right sides of the heart.