General Anatomy/Regulation of Blood Pressure
Blood Pressure is the pressure that blood exerts on the wall of the blood vessels. The pressure originates in the contraction of the heart, in turn, forcing blood out of the heart and into the blood vessels. The concept is more mechanical than biochemical.
There are two mechanisms that take place in the heart, Diastole and Systole. Diastole is the relaxation of the chambers of the heart whereas Systole is the contraction of the heart chambers. This is regulated through measuring your blood pressure of which the normal blood pressure should be around 120/80 to be accounted for at a safe level. The figure 120 is measured through Systole and the 80 accounts for Diastole. The Systolic Pressure will show the pressure that your heart emits when blood is forced out of the heart, whereas Diastolic Pressure is the pressure that your heart shows when it's relaxing. This is the main mechanism by which blood pressure operates.