Exercise 2: Blood Pressure
Blood pressure is the force exerted by the blood on the walls of the systemic arteries. The pressure in the arteries increases as the left ventricle contracts and pumps blood into the aorta. Arterial pressure decreases as the left ventricle relaxes and less blood flows into the aorta. When you get your blood pressure taken, two numbers are measured. First is the systolic pressure which is the force exerted when the left ventricle contracts. Second, is diastolic pressure which is the force left over when the left ventricle is in relaxation. Blood pressure is measured in millimeters of mercury (mm/Hg) on a device called a sphygmomanometer (sfig-mo-ma-nom-e-ter) or blood pressure cuff. Blood pressure is always in flux due to the different demands of the body that we all experience everyday. Average male blood pressure is 120/80 mm/Hg and most females' average 110/70 mm/Hg.
In this exercise you will get to measure your own blood pressure and study the effects of different variables on blood pressure.
Take a look at http://www.sumanasinc.com/webcontent/animations/content/bloodpressure.html.
PROCEDURE
1. You will need to travel to a local grocery store or drug store to find an automatic blood pressure machine. These machines are usually found near the pharmacy. (Providing you with your own blood pressure cuff is cost prohibitive). Take this lab manual with you to the store.
2. Once you find the machine, you will need to sit down and relax for at least five minutes before you take your first blood pressure reading. The five minute wait time is important. Don't rush it. You need to sit and relax.
3. Record the results in the appropriate place in the Lab Report.
4. Get up and walk around the store or outside for five minutes.
5. Go back to the machine and take your second blood pressure reading. (If the machine is taken, keep walking around the store and come back in a few minutes.)
6. Record your second reading in the appropriate place in the Lab Report.
7. For this next reading, you're going to have to rush around a bit. Walk quickly to the other side of the store and back or outside to your car and back. You need to do this quickly. You don't have to run, but a fast walk is necessary.
8. Take a third reading on the machine. Record your results in the Lab Report.
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