Ok here's some insight from a partially medically attuned member...although if you want a superior attitude that's gonna cost ya...
The heartbeat has two phases: diastole - which is the relaxation phase of the ventricle walls in which blood flows into the heart - and systole - in which the walls of the right and left ventricles (chambers of the heart) contract to pump blood into the pulmonary artery and aorta.
Blood pressure is the force that the blood exerts on the arterial walls. When BP is being measured with a spygmomanometer and stethoscope, the vessels in the upper arm are compressed by air pressure until blood flow is stopped in the brachial artery (main artery of the arm). When the air escaped the bag and pressure is lowered slowly blood begins to make its way through the gradually opening artery. The first sound of the pulse beat, which reads on sphygmomanometer as the higher, systolic blood pressure, is the pressure in the artery when the left ventricle is contracting to force the blood into the aorta and other arteries. The beat changes from sounding loud to a soft swishing and this is read as diastolic blood pressure as it is pressure in the artery when the ventricles are relaxing and the heart is filling with blood.
Hope this helps.
Shy
