Exercise causes many factors of homeostasis to kick in to maintain internal equilibrium. How exercise affects some of these factors can be determined by measuring and observing certain conditions of the human body. Some of these conditions are: • change in skin color on arms and face
• perspiration level
• external body temperature
• breathing rate
• heart rate
1. Working in groups of 3 or 4, select a student that will be able to jump rope well and will be able to maintain jumping for 8 minutes. The group member jumping will stop just long enough for the needed measurements and observations to be collected. 2. Record the resting observations and values of the person jumping rope (or doing jumping jacks) using the following measurements:
• skin color of hands and face (pale, pink, red) • perspiration level (none, mild, medium, high) • external body temperature (place the thermometer under the subjects arm pit for 1 minute; the thermometer should be directly against the skin) • breathing rate (count the number of breaths in 1 minute) • heart rate (find the pulse at the wrist and count the number of beats in 1 minute)
1. Make observations and measurements of the person jumping rope while they are sitting down and resting. Record your observations on the data table. 2. The student jumping rope should begin jumping when the person with the stopwatch gives the signal and continue jumping for 2 minutes. After 2 minutes quickly make observations and measurements and record them on the data table. 3. The student will continue jumping rope (or doing jumping jacks) at 2 minute intervals until the 8 minute time period has been completed. After each 2 minute interval observations and measurements should be made. 4. When the 8 minutes is up, the student jumping rope will rest for 1 minute. After 1 minute, observations and measurements will be taken for the final time. Don’t forget to record the data on the data table. 5. Clean the thermometer with alcohol and return it and all other lab materials to the designated area. 6. Make a separate graph for each of the following:
• External Body Temperature at Various Intervals of Exercise • Breathing Rate at Various Intervals of Exercise • Heart Rate at Various Intervals of Exercise
7. Answer the questions in the conclusion section to describe and explain the results of the lab.
Conclusion (NOTE: these are essay questions. To obtain the full available points you must include supporting information along with the ultimate answer. Expect that you will have to write a paragraph with 5-10 sentences for each question):
1. What are the changes you observed in the body color and perspiration level in response to?
The changes in perspiration and body color are due to exercise. When we exercise, we produce extra heat. The body then has to undergo some changes to get rid of this excess heat. Our veins dilate. More heat is transferred from your body to the surrounding environment. Of course when this happens, more blood is near the skin, making it appear either more pink or red.
2. How do the changes help the body adjust to maintain equilibrium (homeostasis)?
The cardiovascular system serves five very important functions during exercise. It helps deliver oxygen to working muscles and oxygenates blood by returning it to our lungs. This system also transports heat from the core to the skin, delivers fuel and nutrients to the active tissues, and transports hormones. Without the cardiovascular system, these changes would not take place and would not be able to maintain equilibrium.
3. Why do you think a change in body temperature occurs?
A change in body temperature must take place when we exercise, or we would all overheat! When people perform strenuous work-outs, they will have a very high body temperature. Homeostasis helps by allowing our bodies to produce sweat. When sweat evaporates off our skin, the body cools down. This results in an overall temperature balance which allows us to continue our work-outs without majorly overheating.
4. Your body uses which mechanisms to maintain a constant body temperature?
Negative and positive feedback mechanisms are used to maintain a constant body temperature. Basically, messages are sent to a part of the brain. We all have a built in “thermostat.” (The brain is the control center for all of the body’s homeostatic processes.) Sweating cools us internally and shivering keeps us warm.
5. Why does an increased breathing rate accompany exercise?
During exercise our muscles need more oxygen and fuel to keep going. As more energy is needed in the muscles, more oxygen is needed in the blood. The respiratory system responds by altering the breathing rate.
6. Why does an increased heart rate accompany exercise?
Blood begins to rush more and our hearts are forced to work harder during exercise. This causes the heart rate to go up. The increase in heart rate boosts speeds at which arteries and capillaries deliver oxygen to those cells in need.
7. Write a paragraph about the conclusions you can draw about your body’s ability to maintain equilibrium (homeostasis). Be sure to include the answers to the questions above.
Homeostasis is the body’s way of maintaining a consistent internal state. The nervous system sends and receives signals about temperature, hydration, and other things. The endocrine system works as a messenger to adjust bodily functions. During exercise, the body’s internal environment is all out of whack. Through homeostatic feedback mechanisms, the body is able to maintain equilibrium.