Systemic arterial blood pressure (BP). Blood pressure is the pressure on the walls of blood vessels when blood flows through the blood vessels. It is the force that pushes blood to flow through the blood vessels. The ventricle contracts and blood flows from the ventricle into the artery, when blood pressure on the artery is highest, called systolic blood pressure (SBP). Ventricular diastolic blood pressure (DBP) is called diastolic blood pressure (diastolic blood pressure).