Name: __________________________________________
Date: _____________
Lab Activity: Maintaining Homeostasis
Introduction:
Homeostasis is one of the fundamental characteristics of living things. It refers to the maintenance of the
internal environment within tolerable limits. Different factors affect suitability of our body fluids, such as blood to
sustain life; these include properties like temperature, salinity (how much salt), pH, and the concentrations of
nutrients and wastes. Because these properties affect the chemical reactions that keep us alive, we have builtin physiological mechanisms to maintain them at desirable levels. When a change occurs in the body, the body
most often responds through what is called a negative feedback loop. The body responds in such a way as to
reverse the direction of change. For example, if your blood sugar was too high, your body would initiate
processes such as secreting increased insulin to lower your blood sugar. Because these processes tend to
keep things constant, it allows us to maintain homeostasis. Due to the increased demands exercise puts on the
body, many homeostatic factors to kick in, in an effort to maintain internal homeostasis. Some of the
observable parameters of homeostatic mechanisms during exercise are:
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Change in skin color on arms and face
Perspiration Level
External Body Temperature
Heart Rate
Breathing Rate
Objectives:
Determine the effect that exercise has on specific body parameters.
Observe the changes in the body that occur during exercise in an effort to maintain homeostasis.
Materials:
Isopropyl alcohol
Stopwatch
Forehead thermometer
Cotton Balls
Procedure:
1. Each group should obtain: a thermometer; stopwatch*Mrs. Buettner has stopwatch
2. Record the resting observations and values of you and your subject for each of the 5 parameters. (Your
lab will contain your partner’s data.)
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
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Record normal skin color of hands and face (i.e. pale, pink, red, etc.)
Record normal perspiration level (i.e. none, mild, medium, high)
Record external body temperature by placing the thermometer on the forehead for 1 minute
Record the resting heart rate using the carotid or radial pulse for 30 seconds (x2)
Record the breathing rate by counting the number of breaths taken in 30 seconds (x2)
3. Have your subject begin to do jumping jacks or jogging in place. Please note your subject should be sure to
exercise at a level that they can maintain for the entire 8 minutes.
4. Take your subject’s parameter readings, using the same techniques described above at the 2, 4, 6, and 8
minute time markers. Be sure to take final readings 2 minutes after your subject has stopped exercising.
Record all of your parameter readings in the table provided.
5. After cleaning the thermometer with alcohol, switch partners. Your partner will now take your measurements.
Clean the thermometer with alcohol when you are finished and return it along with your other lab materials to
the front of the room.
6. Plot you and your partner’s measured data on 3 graphs on a separate sheet of paper and attach them to the
back of your lab. You should plot 1 graph each for body temperature, heart rate, and breathing rate versus the
duration of exercise (i.e. rest(0), 2, 4, 6, 8, 10 minutes). Make sure your graphs contain a title, labeled axes,
and a key.
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Table: Body Parameters
Body Color
You
Partner
Perspiration
Level
You
Partner
Body
Temperature
(ºCelsius)
You
Partner
Heart Rate
(Beats/min)
You
Partner
Breathing
Rate
(Breaths/
min)
You
Partner
At rest
2
minutes
4
minutes
6
minutes
8
minutes
10
minutes
after
Follow-up
Questions:
exercis
e
1) What are the changes you observed in the color of the face and hands? ____________________________
________________________________________________________________________________________
2) What are the changes you observed in perspiration level? _______________________________________
________________________________________________________________________________________
3) What are the changes in color of the face and hands and perspiration level in response to? How do these
changes contribute to the maintenance of homeostasis?
________________________________________________________________________________________
________________________________________________________________________________________
4) Why do you think a change in body temperature occurs? Hint: Think of food as “fuel.” __________________
________________________________________________________________________________________
________________________________________________________________________________________
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5) What happens to heart rate and breathing rate during exercise? Why do you think this happens? Hint: What
does the blood carry?
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
6) Why does an increase in breathing rate accompany exercise? ____________________________________
________________________________________________________________________________________
________________________________________________________________________________________
7) By studying your parameter measurements after exercise has stopped, what conclusions can you draw
about your body’s ability to maintain homeostasis?
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
8) Based on the information you learned in this lab, explain why it is important to drink plenty of water during
exercise and what could possibly happen if you didn’t. Think: What processes would be impaired?
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
Background information: http://www.easternct.edu/personal/faculty/saull/sect9/resous9/cartos9/homeos9.html
Lab activity: http://educ.queensu.ca/~science/main/concept/biol/b06/B06LACW4.htm
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