Heart Physiology

Exercise 3: Measuring a Pulse

 Heart rate is determined by taking a person's pulse or pressure wave in an artery. As the left ventricle contracts (systole), blood pressure increases and stretches the arterial walls. When the ventricle relaxes (diastole) the arterial walls shrink to their relaxed diameter. The change in the vessel diameter is felt as a throb or pulse in various locations in the body. Pulse can be determined at series of pressure points throughout the body. The most common pressure point is the radial artery in the wrist. You also have a strong pulse in the carotid arteries in the neck and the popliteal artery on the posterior side of the knee. 

In this exercise you will measure the pulse in various areas of the body with a friend or family member.

PROCEDURE 

Note:You will need a friend or family member to help you complete this exercise. 

1.     Take out the stopwatch from the LabPaq. 

2.     Have your friend or family member sit and relax for five minutes. Have them take off any watches or bracelets. Don't rush this time. It's important that the person be relaxed to get a good reading. 

3.     Locate your partner's pulse in his or her right radial artery. Use your index and middle finger together. Apply pressure over the radial wrist (thumb side) and then slowly let up. You should feel the pulse beat as you release. It may take several attempts before you find the pulse. People have different pulse intensities. Try several times if you have to.

4.     Once you find the pulse, use the stopwatch to count the beats for 15 seconds. Multiply the number of beats you counted in 15 seconds by 4 to determine the beats per minute. 

5.     Record your observations in Data Table 1. 

6.     Repeat the pulse determination in the carotid artery on the lateral side of the neck and the popliteal artery on the posterior side of the knee. 

7.     Record each result in Data Table 1. 

8.     Have your partner sit in a chair for a minute or so. After one minute, take their radial pulse while sitting and calculate the pulse rate for one minute. Record the results in Data Table 2. Have your partner stand up, and immediately take their radial pulse. Calculate their standing pulse for one minute and record the results in Data Table 2. Now, have your partner jog in place or walk in place for one minute. After one minute take their radial pulse, calculate the pulse rate for one minute and record the results in Data Table 2.