In the blood vessels, the arteries generally have small __________.

Arteries are blood vessels that run throughout the body and carry oxygenated, nutrient-rich blood to organs and tissues. A lumen is the interior space of a blood vessel, including arteries and veins. The size of the lumen can vary and is often related to the function of the vessel. Arteries, which carry oxygen-rich blood away from the heart to the body's tissues, tend to have smaller lumens compared to veins, which return oxygen-poor blood back to the heart. This allows for the high pressure generated by the heart to be maintained as the blood flows through the smaller, more muscular arteries to the smaller arterioles and capillaries, where the exchange of nutrients and waste products occurs.