one cell thick, smooth surface facing lumen

collagen fibres, elastic fibres and smooth muscle

only collagen fibres and elastic fibres

withstand high pressure, prevent rupture of vessels

allows vessel to stretch to withstand high pressure

when blood enters at lower pressure, it recoils to give blood a small push to increase blood pressure

maintain blood pressure

maintain blood pressure

contract/relax to change volume of blood delivered

less elastic tissue and less smooth muscle

closer to the heart

elastic fibres can stretch / recoil to withstand high pressure and smooth out pulsatile flow

further from the heart

smooth muscles can contract / relax to control volume of blood flow

become narrower so blood flow slows down