Lab 8
Vital signs and homeostasis
Introduction
Your body needs to keep many factors at the right level in order to survive. It does that
through the collaboration of all its systems, like the digestive, circulatory and respiratory
system. You can make measurements, to see how those systems are functioning, and to see
how your ‘homeostasis’ is. After the break we will take a look at the nervous, the excretory
and the immune system. Today, in this lab, you will take a look at some of your vital signs.
Do this lab in couples. You will have to work it, to finish in this time period.
This lab has three parts:
PART 1: how to test for different nutrients in food
PART 2: how to measure the shapes your lungs are in
PART 3: How to measure the vitals of your circulatory system
PART 4: Compare: How are you doing?
PART 1: Testing for Nutrients
What nutrients can you find in different foods? In this part you will find out how you can test for different
nutrients.
Do the lab that is described in the small book on page 171. In Your teacher will tell you how to use it.
Test only 3 foods for all of the nutrients. At the end of lab you should have a table in your lab notebook that
looks similar to this:
Food Protein Glucose Starch Lipid Vitamin C Water
Prediction
Food 1
Result
Prediction
Food 2
Result
Prediction
Food 3
Result
Clean up
Clean up your working area and wash your hands before continuing with Part 2.
PART 2 – Your Lungs
Your lungs aid in keeping the CO2 balance in your body in range. The healthier your lungs are, the better they
can do their job. In this part you will investigate how to measure lung capacity. Human lung capacity can be
measured in several ways. One way is using a piece of laboratory equipment called a spirometer. You will do it
using a balloon.
Several different lung volume measurements can be made: the vital capacity, the expiratory reserve, and the
tidal volume. The residual volume of the lungs cannot be measured.
Vital Capacity: The total volume of air that you can breathe out.
Expiratory Reserve: The air you have left in your lungs after you have exhaled.
Tidal Volume: The volume of air that you breathe in a regular breath.
Residual volume: The amount of air that is left behind in your lungs.
You will measure the vital capacity . You will measure expiratory reserve if there is time left. You will need a
Round balloon and a metric ruler.
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Part 2.1, Vital Capacity
All the steps have to be done by each student.
Copy table 1 in your notebook. You will have to give the table the appropriate heading as you go
along.
Stretch a balloon several times so it is not as tight.
Take as deep a breath as possible. Then exhale all the air you can into the balloon and pinch the
balloon closed.
Measure and record the diameter of the balloon in column A of table 1. The figure below illustrates how
you measure the diameter of the balloon.
Table 1
Vital Capacity
Diameter Lung volume in cubic
balloon in centimeters
centimeters
1
2
3
4
5
Average
Run four more trials and record the diameter for the balloon each trial.
ONLY IF TIME – ASK TEACHER Part 2, Expiratory Reserve
Exhale normally.
At the end of the exhalation, DON’T INHALE, but put the balloon in your mouth and
exhale all the air left in your lungs.
Record the diameter of the balloon in column B of table 1.
Measure and record the diameter of the balloon in column B of table 1.
Run four more trials and record the diameter for the balloon each trial.
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Part 2.2 - Conversion of Diameters to volume
To convert from balloon diameter to volume, use figure 2.
Figure 2
Convert each diameter for vital
capacity (and tidal volume) to volume.
Calculate and record your average lung volumes.
PART 2.3 - Breathing Rate
Finally, you can measure your breathing rate as one of the vital signs. Your
breathing rate tells you how efficiently blood is transported to your heart
and how well you are getting rid of CO2.
Measure your breathing rate by counting the number of respirations
in one minute. Record your result.
PART 3 – Your heart
Finally, you can receive information about your homeostasis, by measuring you
heart rate and pulse rate.
PART 3.1 - Finding your Pulse
Read tall instructions.
Locate the pulse in your wrist. Look at the figure on the right to help
you. Don’t use your thumb, but use two fingers.
Locate the pulse in your neck. Again, use the picture.
What causes a pulse?
How do the pulse in the wrist and the neck feel different?
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PART 3.2 – Pulse Rate
Fill in the information in the table below:
Your data Your partners data
Resting Pulse
Pulse after exercise
Pulse after 1 minute rest
Pulse after 2 minutes rest
Obtain a stopwatch. Set the stopwatch to zero. Sit quietly in a chair for a few mimics and breathe
normally. Find the pulse in your wrist. When you have located a strong pulse, have your partner begin
timing 15 seconds with the stopwatch. During the 15 seconds, count the number of beats you feel.
Multiply the number of beats obtained for the 15-second interval by four to find your pulse rate in
beats per minute. Record your pulse rate in beats per Minute on the table.
Switch roles with your partner and repeat step 1 of Part A. Be sure to set tile stopwatch to zero before
beginning.
Run in place for three minutes. At the end of the three minutes. Locate your pulse. Count the number
of beats you feel while your partner times a 15-second interval. Do this immediately after exercising,
one minute after exercising, and two minutes after exercising. Multiply the number of beats for each
15-second interval by four to find your pulse rate in beats per minute. Record these values on the.
Switch roles with your partner and repeat step 3 of Part A.
PART 3.3 – Heart Rate
Fill in the information in the table below:
Your data Your partners data
Resting Heart Rate
Heart Rate after exercise
Heart Rate after 1 minute rest
Heart Rate after 2 minutes rest
Obtain a stethoscope and a stopwatch. Sit quietly in a chair for
a few minutes and breathe normally. Wipe the tips of the
stethoscope with a tissue and place them in your ears so they
are comfortable. Place the diaphragm of the stethoscope to
the left side of center on your chest. Make sure that any
buttons or jewelry are not in the way. Move the diaphragm of
the stethoscope until you locate your heartbeat.
Once you have located your heartbeat, have your partner set
the stopwatch to zero, then begin timing 15 seconds. Count
the number of times your heart beats during this 15-second
interval. Multiply this number by four to find your heart rate in
beats per minute. Record this value on the table.
Switch roles with your partner and repeat step 2 of Part B. Be sure to wipe the ear tips of the
stethoscope.
Wipe the ear tips of the stethoscope. Run in place for three minutes. At the end of three minutes, use
the stethoscope to locate your heartbeat. Count the number of times your heart beats while your
partner times a 15-second interval. Do this immediately after exercising, one minute after exercising,
and two minutes after exercising. Multiply the number of beats for each 15-second interval by four to
find your heart rate in beats per minute. Record these values in the table.
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Switch roles with your partner. Repeat step 4 of Part B. Be sure to wipe the eartips of the stethoscope.
Before leaving the laboratory, return your equipment to its proper location.
PART 4 – How are you?- Review and Analysis
1. Fill in the blanks in the table below:
To test for Use: You can tell by
Water
Biuret
Glucose Solution turns to
red when heated
Starch
2. Record the vital capacity and expiratory reserve for you and your partner in one bar graph. You have
to design an appropriate scale for both axis and decide what value goes on the X and what value
goes on the Y.
3. Create ONE graph, that shows the pulse rate and the heart rate for you and your partner. This means one
graph with 4 lines! Label both axis, label each of the lines AND name the graph.
4. Take a look at the range of normal vital signs in the table below:
Vital Sign Normal Range
Breathing Rate 10-20 resp/minute
Heart Rate 60-100 beats/minute
Vital Capacity 4000
Expiratory Reserve 1000
a. Describe for each vital sigh how the normal range compares to your value.
b. What may be the reason for differences?
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