Understanding Blood Pressure Measurements

When and where does the measurement of systolic or diastolic blood pressure take place?

1) At the base of the heart
2) At the apex of the heart
3) At both the base and apex of the heart
4) At neither the base nor apex of the heart

Final answer:

The measurement of systolic and diastolic blood pressure occurs at the brachial artery in the arm, not at the base or apex of the heart. A device called a sphygmomanometer is used, with the systolic and diastolic pressures indicated by the sounds heard as air pressure in the cuff is released.

Explanation:

The measurement of systolic and diastolic blood pressure occurs at neither the base nor the apex of the heart. Instead, it is typically measured at the brachial artery in the upper arm using a device called a sphygmomanometer. The systolic pressure, which is the higher number in a blood pressure reading, represents the arterial pressure when the heart's ventricles contract and eject blood. The diastolic pressure, the lower number, indicates the arterial pressure when the heart's ventricles are relaxed and filling with blood.

When measuring blood pressure, the inflatable cuff of the sphygmomanometer is wrapped around the upper arm and inflated to a pressure higher than the systolic pressure, cutting off blood flow through the brachial artery. As the pressure in the cuff is slowly released, the systolic pressure is indicated by the first audible tapping sound heard through a stethoscope, which is the sound of blood beginning to spurt into the artery. The disappearance of this tapping sound corresponds to the diastolic pressure, indicating blood is flowing freely through the artery again.