PATHOLOGY

Detailed explanation-1: -These are blood vessels that carry oxygenated blood from the heart to the tissues. These have thick-walled and narrower lumens because they carry blood from the heart with great pressure.

Detailed explanation-2: -Arteries have narrow lumen because the blood from the heart comes into the arteries with a lot of pressure. Due to this reason, arteries are thick walled so that they do not burst. Hence, to maintain the same pressure, arteries have narrow lumen.

Detailed explanation-3: -Blood capillaries have a very thin lumen for the proper exchange of nutrients and gases. The lumen of the capillaries is very small because the blood flow here is too slow for the maximum exchange process. The capillaries also lack thick muscular walls.