The human circulatory system is a complex network that transports blood throughout the body. It consists of the heart, blood vessels, and blood. The heart pumps oxygen-rich blood from the lungs to the rest of the body, while oxygen-poor blood returns to the heart to be sent back to the lungs for oxygenation. Blood vessels are categorized into three types: arteries, veins, and capillaries. Arteries carry blood away from the heart, veins return blood to the heart, and capillaries facilitate the exchange of oxygen, nutrients, and waste between blood and tissues. This system is essential for maintaining overall health and homeostasis.