AP LAB #10: Blood Pressure (modified)*
Measurable Indicator of the Health of the Circulatory System!
Lab Objectives. At the completion of the lab, you should be able to:
• measure pulse or heart rate (HR) and respiratory rate (RR);
• measure blood pressure (BP);
• describe the relationship between HR, RR, and BP relative to changes in body position;
• describe the relationship between HR, RR, and BP and isotonic exercise.
BACKGROUND INFORMATION:
An important measure of the health of the circulatory system is blood pressure, or the force of the blood against the walls of the arteries in the body. Arterial blood pressure is affected by the amount of blood pumped by the heart per minute (cardiac output) and the resistance to blood flow through the arterioles (peripheral resistance).
To measure arterial blood pressure, we use a device known as a sphygmomanometer (hereafter abbreviated “sphyg”). This device consists of an inflatable cuff connected by rubber hoses to a hand pump and to a pressure gauge graduated in pressure units (mm Hg). The cuff is wrapped around the upper arm and inflated to a pressure greater than the expected systolic pressure, thus closing down the brachial artery in the arm. The examiner places the bell of a stethoscope in the inside of the elbow below the biceps muscle to pick up the sounds of the blood in the artery as the pressure in the cuff is allowed to fall. (This is done gradually by opening a screw valve next to the hand pump.) At first there is no sound; then, a sharp, tapping sound of blood spurting through the partially-opened artery at systolic pressure; and ultimately, no sound as even the low-pressure blood (@ diastolic pressure) can get through the completely open artery. (The various sounds heard with the stethoscope are known as the sounds of Korotkoff.)
Blood pressure is recorded as: systolic pressure (mm Hg) / diastolic pressure (mm Hg). A normal blood pressure measurement for a given individual depends on the person’s age, sex, heredity, emotional state, body weight, etc. For young men and women at age 17-18, the normal BP’s will range from 100-120 mm Hg systolic pressure, and from 60-80 mm Hg diastolic pressure.
One “high” BP reading may not indicate a health problem; BP needs to be measured over several days at different times of the day by a health care professional before a true measure is achieved. Blood pressure measurements that are chronically elevated may indicate poor cardiovascular health. This condition, called hypertension, is a major contributor to heart disease and stroke.
EXPERIMENTAL PLAN:
Materials:sphyg’s, stethoscopes, stool or chair, stopwatch, data table, graph paper
Procedure:
*students should work in groups of 3 or 4 – one should volunteer to be the “subject”
*practice taking a classmate’s pulse before collecting data
*practice taking a classmate’s blood pressure before collecting data
*subject should practice taking their own respiratory (breathing) rate
**the room must be QUIET while readings are being taken!!!
1) Take a few moments to listen to your heart and the heartbeat of the “subject” student. Place the bell of the stethoscope about 3 cm to the left of the sternum (breastbone) at the space between the 5th and 6th ribs. The heart sounds are heard as a loud “lub” sound followed by a softer “dub” sound.
2) In your lab group, assign the following roles: subject (can count their own respiratory rate), HR measurer/recorder, RR measurer/recorder, & BP measurer/recorder.
3) Take a BP measurement for practice.
a) The person to have his/her BP measured should be seated,
with sleeves rolled up (loosely).
b) Wrap the cuff of the sphyg snugly around the upper arm.
(Arm needs to be about heart height).
c) Place the bell of the stethoscope directly below the cuff
in the well of the elbow joint.
d) Close the valve of the bulb (turn it clockwise). Inflate the
cuff with rapid squeezes of the bulb until the
pressure gauge reads UNDER 200 mm Hg. (Don’t go higher than!)
e) SLOWLY turn the valve of the bulb so that air begins to
GRADUALLY escape from the cuff.
f) Listen for the first heart sounds (a “tapping” pulse). The pressure
on the gauge when you first hear these sounds is the systolic pressure.
g) Continue to listen until the thumping sound of the heart
fades to nothing. The pressure at the moment of
silence is the diastolic pressure.
NOTE: If you failed to read the gauge correctly or missed the sounds during BP measurement, you must deflate the cuff completely and allow the subject to relax for a few minutes before starting over.
4) Do the lab!
BLOOD PRESSURE LAB DESIGN:
Activity A: The Harvard Step Test – a measure of endurance (isotonic exercise).
1) Determine a baseline HR, RR, and BP with the subject sitting comfortably.
*Use the RADIAL PULSE for heart rate counting.roup may switch the role of "nt and then multiply that number by 4 for the number in 1 minute..
*For HR you can take a 15-second pulse count and then multiply that number by 4 for the number in 1 minute.
2) Instruct the subject to place his/her right foot on a chair (The Harvard Step Test requires an 18 inch stool!). STABILIZE THE CHAIR FOR THEM SO THEY DON’T FALL. Your subject must raise his/her body so that the left foot comes to rest by the right foot. Return left foot to original position. Repeat this exercise for 3 minutes of stepping up/down on the stool.
3) IMMEDIATELY after the completion of the stepping, measure the HR, RR, and BP. (Subject should be sitting down for the measurements)
4) Measure HR, RR and BP measurements 3 minutes post-exercise and 6 minutes post-exercise to allow us to study “recovery.”
5) Record all measurements as team data. Calculate the “Mean Arterial Pressure” for each set of data.
Mean Arterial Pressure = Diastolic Pressure + 1/3 (Systolic – Diastolic Pressure)
Activity B: “Real Age” and Life Expectancy – complete at home using the following internet sources:
1. To calculate your “real age” go to the following website:
2. Select option: “Take the Real Age Test.”
**NOTE: the site will only calculate your “real age” if you are 20 years old…so enter your birthdate as if you are 20 years old and answer the rest of the questions…see what your “real age” will be at the age of 20 if you continue with your current habits.
3. Take the quiz and calculate your “RealAge”!
a) At the conclusion of the “quiz,” calculate your “real age”.
b) Check out the “Recommendations” for a healthier lifestyle.
4. To calculate your “life expectancy”, go to the following website:
5. At the conclusion of the “Longevity Game,” write down your longevity age.
RESULTS:
1) Completed data table for blood pressure / exercise experiment.
2) Construct TWO graphs of team data.
● the first one is a multiple-line graph for the heart rate and breathing rate data;
● the second one is a multiple-line graph for the blood pressure data (systolic, diastolic, and mean)
Most Common Causes of Death, United States, 2001*
Name Date Per
TEAM DATA TABLE for BLOOD PRESSURE LAB
ACTIVITY A: “Harvard Step Test” – Physical Fitness Test
Measurements taken: / 15 sec. heart rate (x 4) / Breaths per minute / Systolic Pressure / Diastolic Pressure / *Mean Arterial PressureBaseline
Immediately after exercise
3-min after exercise
6-min after exercise
*Mean Arterial Pressure = Diastolic Pressure + 1/3 (Systolic – Diastolic Pressure)
POST-LAB DISCUSSION – BLOOD PRESSURE LAB
1) Determine your own heart rate (beats per minute). Record here:
2) CARDIAC OUTPUT is the amount of blood moved by the heart. Cardiac output depends on both the rate the heart is beating and the volume of blood the hart moves with each beat (the STROKE VOLUME). Assume a cardiac output of 5 liter/minute and use your resting heart rate to calculate your approximate stroke volume:
Stroke volume=cardiac output / heart rate
Stroke volume = 5 liters per minute / your heart rate =
3) What happened to the subject’s heart rate when they exercised?
4) What happened to the Mean Arterial Pressure (MAP) during exercise?
5) Explain why high blood pressure is a health concern.
6) Explain why an athlete must exercise harder or longer to achieve a maximum heart rate than a person who is not as physically fit.
7) Research and explain why smoking causes a rise in blood pressure.
8) Ectotherms (cold-blooded organisms), such as an earthworm, will show a decrease in heart rate in a cold environment, and an increase in heart rate in a warm environment. Why is this?
9) Do endotherms (warm-blooded organisms) show the same results described in #8? Why or why not?
10) Describe at least four ways an ectothermic organism’s behavior helps it regulate its temperature.