The arterial pulse pressure (shown as the grey band around the mean pressure in the figure) increases as the blood flow travels down the aorta and into distributing arteries. The systolic pressure rises and the diastolic pressure falls, therefore the pulse pressure increases. This occurs because of reflective waves from vessel branching and from decreased arterial compliance (increased vessel stiffness) as the pressure pulse travels from the aorta into distributing arteries. As the blood flows into smaller arteries and arterioles, the pulsatility declines.