Blood vessels form an intricate network responsible for circulating blood throughout the body. They include arteries, veins, and capillaries. Arteries carry oxygenated blood from the heart to tissues, branching into smaller vessels. Veins return deoxygenated blood to the heart. Capillaries, tiny vessels, facilitate nutrient and oxygen exchange between blood and tissues. The vascular system regulates blood pressure, transports nutrients, removes waste, and regulates temperature. Endothelial dysfunction or damage can lead to conditions like atherosclerosis.