So once again, arteries have a thick layer of smooth muscle which gives them the ability to recoil during expansion. This means that when the blood pushes against the walls of these arteries they can push right back. Therefore, when the blood fills these arteries and it tries to expand them the expansion doesn't actually take place or it takes place but only a very small percentage of expansion actually takes place. So for relatively large arteries such as our femoral artery, the femoral artery it only expands by about 10%. So in diagram A we have the relaxed state of our artery and no blood actually flows across. But when blood actually fills the arteries the fluid, the blood pushes against the walls but the walls push right back and so it expands only by a tiny amount and that means that arteries have a low compliance.