Blood Pressure, Measurement Of
Blood pressure is often measured using a noninvasive technique called a sphygmomanometer. Sphygmomanometer is derived from the Greek word sphygmos, meaning “pulse.” A cuff is wrapped around the upper arm of the individual and inflated to a level which is much higher than the expected systolic blood pressure measurement. Then a stethoscope is placed over the brachial artery and when no sounds are picked up it means the artery has been collapsed by the pressure against the walls preventing blood from flowing. Systolic blood pressure is measured by slowly releasing the pressure in the cuff until it eventually reaches a point where tapping sounds are heard, which is caused by blood spurting with each pulse. This occurs during ventricular contraction. Diastolic blood pressure is measured by continuing to let the air out of the cuff, and when sounds are no longer heard, a reading is taken; no sounds mean blood is continuously flowing...
References and Further Reading
- Andreassi, J. L. (2006). Psychophysiology: Human behavior and physiological response. Hillsdale: Lawrence Erlbaum Associates.Google Scholar