Blood Pressure Determination
Purpose: The purpose of this exercise is determine one's blood pressure with a sphygmomanometer and stethoscope, and to understand what the higher systolic and lower diastolic readings mean.
Materials and Methods: This investigation requires a sphygmomanometer and a stethoscope and two student volunteers.
Apply the cuff of the sphygmomanometer around the lower part of the arm. Place the stethoscope over the brachial artery on the lower, anterior part of the arm. Pump the cuff up to about 140 mm. and then allow the air to escape from the cuff by pressing the valve below the pump. As the air escapes, listen for the first sound which is caused by turbulence as blood resumes flow through the brachial artery. Note where the *needle or mercury is at this time because that is the systolic reading (systole). Also note that at systole, the needle or mercury will begin "bouncing." Continue listening until the sound disappears. The disappearance of the turbulent sound represents the diastolic value (diastole). Note where the mercury column or needle is located when the sound is no longer heard.
Experiment: Note the diagram below as you carry out this investigation. Write your systolic and diastolic readings next to the diagram.
Conclusion: What does systole mean?
What does diastole mean?
When the cuff of the sphygmomanometer is inflated, what happens to the brachial artery?
*needle if using an analog sphygmomanometer, mercury is using a mercury column type sphygmomanometer....the diagram above demonstrates the latter....