What is the main function of the heart?

The primary function of the heart is to pump blood throughout the body. This action is crucial as it ensures the delivery of oxygen and essential nutrients to tissues and organs while also facilitating the removal of carbon dioxide and metabolic wastes. The heart's rhythmic contractions propel blood through a network of vessels, maintaining circulation which is vital for sustaining life.

In this role, the heart operates as a central component of the cardiovascular system, working in tandem with blood vessels and blood to support various bodily functions. Understanding this function highlights the heart's significance in overall health, as any impairment in its ability to pump effectively can lead to serious health issues.

The other options represent important physiological processes that involve different systems in the body but do not directly relate to what the heart primarily does. For instance, filtering blood is primarily a function of the kidneys, hormone production is typically associated with endocrine glands, and temperature regulation is managed by the hypothalamus and other parts of the body.