Investigating Factors that Affect Heart Rate and Blood Pressure
Blood pumped through blood vessels is always under pressure. This
pressure is highest in the arteries closest to the heart and gradually
decreases as the blood travels around the body. Blood keeps moving
around the body because there are differences in pressure in the blood
vessels. Blood flows from higher-pressure areas to lower-pressure
areas until it eventually returns to the heart. Blood pressure is
controlled by three things: heart rate, stroke volume and peripheral
resistance. Generally, when heart rate increases, blood pressure
rises, and vice versa. A number of things affect heart ...view middle of the document...
Generally, a change in any factor that may cause the blood pressure to
rise is balanced by a change in another factor. This is how the body
keeps blood pressure in a normal range.
The purpose of this lab is to identify the difference between blood
pressure and heart rate, and to analyze the factors that may affect
them. Time will be an independent variable.
1. Measure the sitting heart rate.
a. Feel with the fingertips of your index and middle finger for
your pulse point until you detect pulsations.
b. Keep yourself as still as possible while you are taking your
c. Count the number of heartbeats you feel in one minute. Record
d. Repeat the procedure for your partner.
e. Graph and compare results.
3. Measure the sitting blood pressure.
a) Student patient should extend arm on table with palm up.
b) Place blood pressure cuff above the bend in the arm. The cuff
should be snug yet have enough room to insert two fingers.
c) Check to see if valve is open or closed.
d) Place stethoscope ear tips into ear.
e) Position stethoscope on arm to hear pulse.
f) Pump pressure up to 160 mm.
g) Release valve slowly.
h) The first pulse sound you hear as you release the valve is the
i) Have the student patient place their finger on the number of the
first sound to mark the spot.
j) Continue to release the valve. Approximately 40 mm down from the
first sound you will hear is called the diastolic pressure.
k) Record the systolic and the diastolic pressure on the chart.
3. After lying for 5min measure the lying heart rate and blood
4. Choose factors that...