Chambers of the heart with thicker myocardium are able to pump blood with more pressure and force compared to chambers of the heart with a thinner myocardium. to withstand the pressure of the blood coming out from the heart arteries need to thick walls
From the capillaries, blood passes into venules, then into veins to return to the heart. Arteries and arterioles have relatively thick muscular walls because blood pressure in them is high and because they must adjust their diameter to maintain blood pressure and to control blood flow.
