Download Page 1 of 5 Lab # 1. Human Circulation of Blood on Earth ME 5950

Lab # 1. Human Circulation of Blood on Earth
ME 5950/6950 Biofluid Dynamics: From Earth to Space
Spring 2016
Instructor: William W. Liou, PhD
Time Required: ~ 100 min
The circulatory system is responsible for carrying oxygen, carbon dioxide, nutrients, hormones and many
other substances throughout the body. The body's cells rely on the circulatory system for a continuous
supply of essential materials and waste removal. The continuous movement of the blood is driven by the
heart. In it, the ventricles are the pumping chambers of the heart that push blood out of the heart and the
atrium receive the returning blood. This process continues nonstop for many decades – billions of times
during your lifetime.
Following this lab activity, you will better understand how the circulatory system works on Earth.
Throughout the activity, consider how this would be different in microgravity, lunar gravity (16.5% of
Earth’s gravity) and Martian gravity (38% of Earth’s gravity). As NASA’s space exploration programs
move forward, researchers must consider how the human body will adapt in different conditions and for
different lengths of time. In order for humans to have a more permanent presence in space, precautions
will need to be taken to ensure the health of the astronauts. You will be asked to hypothesize how the
human circulatory system will be affected on long duration missions and in environments with
gravitational forces different from Earth. You will also be asked to propose countermeasures that could be
used to maintain cardiovascular health.
Lab Objectives
• Develop an understanding of and measure human blood pressure.
• Gather and analyze your heart rate data under various conditions.
• Enter, graph and analyze data.
Materials/Equipment needed
• sphygmomanometer
• Wearable devices
• Stopwatch
• Step
Pre-Lab Questions
The force with which the ventricles push out blood is called systolic pressure. The force that the blood
exerts on the walls of the arteries when the ventricles relax is called diastolic pressure. Together, these
two pressures represent the numbers in a blood pressure (BP) measurement, written as
systolic pressure/diastolic pressure.
1. The pulmonary artery takes blood from the right ventricle to which body organs?
2. The aorta, which is the largest artery in your body, takes blood from the left ventricle. What is the
destination of this blood?
3. Which of the two values in a BP reading is always greater?
4. What is a "sphygmomanometer"?
5. An example of a BP reading is 120/70. What does this reading represent?
Parts of the materials are adopted from NASA Research Laboratories Series: 554061main_AP_ED_CirculatorySystemLab_Nspire)
Page 1 of 5
Experiment I. Arterial Blood Pressure Measurement
Procedures
1. With the subject seated, apply the cuff of the
sphygmomanometer around the upper arm of the
subject so that the hosing for the cuff is positioned
over the cubital fossa.
2. Apply the bell of the stethoscope to the skin over the
brachial artery in the cubital fossa.
3. Close the screw valve on the hand pump and pump
the cuff to a pressure of ~160 mmHg. Do not exceed
180 mmHg.
4. Open the screw valve on the pump to slowly release
.
the pressure, listening to the brachial artery through
Measurement of blood pressure with a
the stethoscope and noting at what pressure the
sphygmomanometer and stethoscope.
sounds of Korotkoff (the sounds generated by blood
Image from http://www.merck.com/mmhe/
turbulence in a partially occluded artery) begin
(systolic pressure) and end (diastolic pressure). Record these values.
5. Calculate and record the pulse pressure for the subject as follows:
Pulse Pressure = Systolic BP – Diastolic BP
6. Calculate and record the mean arterial pressure for the subject as follows:
Mean Arterial Pressure = Diastolic BP + 1/3 (Pulse Pressure)
7. Switch roles and have your partners find his/her blood pressure.
Experiment II. Pulse Measurement
Procedures:
1. Sit down and place either hand palm up on a
table top. Fact the palm and use the index and
middle finger from your other hand to locate
your pulse. Your radial artery is on the thumb's
side (or outside) of your wrist when the palm
of your hand is facing you.
2. Place your fingers half way between the
tendons that run down the center of your
forearm and the edge of your arm, on the
thumb side, right at your wrist. You should
feel a strong pulse here. Record the data.
3. Stand upright for one to two minutes. Find
your heart rate in beats per minute (BPM) by
taking your radial pulse. Count the beats while your partner times 30 seconds on the stop watch or
clock. Multiply this number by two to find your BPM. Record the data.
4. Switch roles and have your partners find his/her heart rate. Record the data.
5. Lie down on a lab table or the floor for one to two minutes until you are totally relaxed.
6. Find your heart rate as you did before and record the data. Remain lying down.
7. Rest for one to two minutes, then stand up quickly and immediately take your pulse. Record your
BPM.
8. Switch roles and gather data for your partner. Record the data.
Page 2 of 5
Analyze and explain
1. Why your heart rate is lower when you are at rest.
2. Why might you feel dizzy when you stand up quickly from a lying down position?
3. Why does your heart rate increase right after you stand up from a lying-down position
Experiment III. Cardiovascular Fitness.
The activities in this exercise evaluate the ability of the cardiovascular system to compensate for changes
in body position (which alter the effects of gravity on circulation) and changes in activity (a brief amount
of exercise).
Also, you will evaluate your cardiovascular fitness using an old but very reliable index called the
Schneider index (developed by E.C. Schneider and published in the Journal of the American Medical
Association in 1920).
This is a low intensity exercise. However, if you have any potentially serious cardiovascular conditions
(e.g., chronic severe hypertension, heart disease, etc.) that could be aggravated by these activities, please
have someone else in your group to serve as the subject for this activity.
Activity 1. Reclining Heart Rate.
1. Have the subject recline on the lab table for a period of 5 min
2. Record reclining heart rate by measuring radial pulse for 30 seconds and multiplying that value
by two. Record this value.
3. Measure the subject’s blood pressure with a sphygmomanometer and record this value.
4. Score points for the individual based upon their reclining heart rate:
Activity 2. Standing (Normal) Heart Rate.
1. The subject should stand up and their pulse should be immediately measured for 30 seconds then
multiplied by 2. Record the data.
2. At 30, 60, 90, and 120 seconds after standing up, measure and record the subject’s blood
pressure.
3. Score points for the individual based on
a) how much systolic blood pressure changed upon standing
b) standing pulse rate upon standing, and
c) how much pulse rate increased upon standing.
Page 3 of 5
Activity 3: Changes in Heart Rate with Exercise
1. Have the subject step up onto an 18” stool, right foot first, then bring up the left foot and place it
next to your right. Step down with the left foot and then bring the right foot down to the floor
next to it. Repeat this exercise five times, allowing three seconds total time for each repetition.
2. Immediately after completion of the fifth repetition, measure the subject’s heart rate for 15
second and multiply the number of pulses for 15 seconds. Record this value.
3. Repeat the 15-second pulse measurements at 30, 60, 90, and 120 seconds post-exercise. Record
the time it takes the pulse to return back to normal rate.
4. Score the subject based upon
a) the difference between heart rate immediately post-exercise and normal standing heart
rate and
b) The time needed for heart rate to return to normal standing rate after cessation of
exercise.
Page 4 of 5
Analyze and explain
1.
2.
3.
4.
Describe the trend you see in the data for both you and your partner.
Why does your heart rate increase during exercise?
What other physiological changes do you notice during exercise?
What factors could contribute to a lower heart rate during exercise and a faster recovery after
exercise?
You may know someone who has been diagnosed with "high blood pressure" (HBP), or hypertension. In
general, a person who has a BP reading greater than 140/90 is considered to have HBP. A BP reading less
than 120/80 is considered to be "normal". There are many variables to consider, however, so these values
should be used only as benchmarks.
5. What do you think are some contributing factors to a person having HBP?
6. What are some ways that a person with HBP could lower his/her blood pressure?
Page 5 of 5