Blood Pressure Measurement Lab
Learning outcomes of the lab exercises:
1. Understand the process for measuring blood pressure
2. Obtain blood pressure measurements from subjects following various activities
3. Calculate pulse pressure and mean arterial pressure from the measurements
4. Interpret blood pressure values in a physiological context
Introduction:
Blood pressure is the pressure exerted on the surface of blood vessels by blood. This pressure circulates blood through arteries, veins, and capillaries. The increased pressure that results from blood leaving the heart is the systolic pressure. When the heart relaxes, the arteries return to their original diameter and, in the process, squeeze blood forward through the cardiovascular system. This pressure when the heart relaxes is the diastolic pressure.
Is blood pressure the same throughout the circulatory system? How do you know?
Blood pressure, like barometric pressure, is measured in units called millimeters of mercury (mmHg). This unit is based on a measuring device called a manometer, which is an inverted tube of liquid mercury. Pressure against the mercury reservoir at the base of the tube raises the column of mercury - the more pressure, the higher the column. Thus, the greater the number of millimeters of mercury, the greater the pressure. For example, a pressure of 100 mmHg would raise a column of mercury 100mm, whereas a pressure of 160mmHg would raise a column of mercury 160mm.
Blood pressure is usually measured in the brachial artery of the upper arm. Systolic pressure there typically ranges from 100 to 140 mmHg, with the average being near 120. Diastolic pressure typically ranges from 70 to 85 mmHg, with an average of about 80. Blood pressure is reported as systolic pressure/diastolic pressure. Thus, a typical blood pressure is "120 over 80" (expressed as 120/80).
