Arteries have much thicker walls than other blood vessels in order to withstand the higher blood pressure that propels oxygenated blood away from the heart. Arteries are also supported by thick muscles and elastic fibers, unlike veins and capillaries, which are subjected to a much lower level of blood pressure.
Arteries are the largest of the body's blood vessels and must be able to withstand the tremendous pressures produced by the heart. Arteries branch out to become arterioles, which are smaller and thinner but still able to handle greater pressure than veins and capillaries. The smooth muscle and tough connective tissue that supports both arteries and arterioles give them the superior strength and elasticity needed to withstand surges of oxygenated blood that travel from the heart.
Arterial walls can also narrow over time or if they suffer damage that leads to the build-up of cholesterol and other fats, limiting the amount of blood that is able to flow through them. Narrow, hardened or occlude arteries can lead to many serious and life-threatening medical conditions, including heart attack and stroke. Despite their thick walls, arteries can also rupture, resulting in a condition known as an aneurysm, which may also create a life-threatening medical emergency.