Which chamber of the heart has the thickest muscular wall?

The left ventricle has the thickest muscular wall of all the heart's chambers. This is due to its critical role in the circulatory system. The left ventricle is responsible for pumping oxygenated blood to the entire body, which requires generating a significant amount of pressure. The thick muscular walls, primarily composed of cardiac muscle, enable the left ventricle to contract forcefully enough to overcome the systemic vascular resistance.

In contrast, the other chambers, such as the right atrium and right ventricle, have thinner walls because they handle lower pressure environments. The right ventricle pumps blood to the lungs, which only requires a modest amount of pressure compared to the systemic circulation. Similarly, the left atrium's main function is to collect blood returning from the pulmonary veins, where pressure requirements are also lower. The anatomical and functional demands on each chamber dictate the thickness of their muscular walls, making the left ventricle uniquely adapted for its role.