What is the primary function of the circulatory system?

The primary function of the circulatory system is to transport nutrients and oxygen throughout the body. This system consists of the heart, blood vessels, and blood, which work together to ensure that essential substances reach cells and tissues that require them to function correctly. Oxygen is vital for cellular respiration, which produces the energy needed for all bodily processes, while nutrients such as glucose, vitamins, and minerals are necessary for growth, repair, and overall health.

While the circulatory system does play roles in supporting other systems—such as the respiratory system by delivering oxygen and removing carbon dioxide—the central emphasis is on transport. Additionally, the regulation of body temperature and aiding in digestion are secondary functions that can be influenced by the circulatory system, but they do not encapsulate its primary purpose, which revolves around the movement of materials essential for life.