3. Precapillary Resistance Vessels Small arteries and aster Less elastic than the larger Arteries arteries Have a thicker layer of Metarterioles act as a Precapillary bypass channel and sphincters regulate flow into smooth muscle Arteriole capillary beds Venule smooth Capillaries Provide the greatest resistance to blood flow through the arterial system Sm venule since they have narrow lumina Arteriovenous bypass Precapillary sphincters3. Precapillary Resistance Vessels – Small arteries and arterioles ➢ Less elastic than the larger arteries ➢ Have a thicker layer of smooth muscle. ➢ Provide the greatest resistance to blood flow through the arterial system ➢ since they have narrow lumina