What are the three main jobs of the heart muscle?

The three main jobs of the heart muscle are to pump blood throughout the body, maintain blood circulation, and facilitate the exchange of oxygen and carbon dioxide in the lungs. The heart contracts rhythmically to propel oxygen-rich blood to the tissues and organs, while simultaneously receiving deoxygenated blood for reoxygenation. Additionally, it helps regulate blood pressure and ensures that all body systems receive the necessary nutrients and oxygen for proper functioning.