What is the primary role of the heart in the circulatory system?

The primary role of the heart in the circulatory system is to function as a pump that contracts and ejects blood. This contraction creates the necessary pressure that propels blood throughout the body, delivering oxygen and nutrients to tissues while also facilitating the removal of waste products like carbon dioxide. The heart's distinct structure, including its chambers and valves, enables it to efficiently pump blood in a coordinated manner, ensuring that circulation meets the body's metabolic demands.

In this context, while filtering blood impurities, acting as a reservoir for excess blood, and regulating blood pressure are functions related to the circulatory system, they do not define the heart’s primary role. The heart's main function is focused on maintaining adequate blood flow through rhythmic contractions, making it essential for sustaining life and overall physiological function.