# Biology II Chapter 28 Homeostasis and Exercise Lab B - Period 5

Biology II Chapter 28 Homeostasis and Exercise Lab B - Period 5

Name(s) __________________________________________________________________Biology IIChapter 28Homeostasis and Exercise LabBackground: Your body’s temperature, heart rate, and blood pressure need to remain within certain set ranges.In this lab, you will work in groups of 4 or 5 to examine the effects of exercise on the circulatory and respiratorysystems and on perspiration level. You will then observe how the body reacts when exercise is stopped.Problem: How does exercise affect a person’s heart rate, breathing rate, and perspiration level?Procedure:1. Choose one volunteer to jump rope at a pace that can be maintained for eight minutes. Make sure thevolunteer is inactive for a few minutes before the experiment begins.2. Measure the heart rate by taking his or her pulse. To take the pulse, place your 2 nd and 3 rd fingers on thevolunteer’s wrist where it meets the thumb. Press very lightly to feel the pulsations. Count the number of beatsin 15 seconds while another student uses a stopwatch to tell you when to start and stop.3. Multiply the number of beats in 15 seconds by 4 to calculate the beats per minute. Record the data in theTable 1 (at 0 minutes). (# of beats x 4 = beats per minute)4. Measure the person’s breathing rate by counting the number of beats per minute. Multiple this number byfour to calculate breaths per minute. Add this information to the table at 0 minutes. (# of breaths x 4 = breathsper minute)5. Rate the person’s perspiration level from 0 to 5 (0 = not perspiring, 5 = dripping). Record in Table 1.6. Write a hypothesis about the effect of exercise on heart rate, breathing rate and perspiration. Remember thata good hypothesis is a complete sentence explaining what you believe will happen. The hypothesis should also beable to be read separate from this lab and still make sense!_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Time (Min)0246810 (rest)Table 1: Effects of ExerciseHeart RateBreathing Rate(Beats/Min)(Beats/Min)Perspiration Level7. Have the volunteer jump rope for 2 minutes. Caution: If the person jumping rope feels discomfort at any time,stop the experiment and inform your teacher.8. After 2 minutes, measure heart rate, breathing rate and perspiration level and record in the table. Take thesemeasurements as quickly as possible and have the volunteer resume exercising.9. Repeat 3 more times and record your data at each point.10. After the final recording, wait 2 minutes with the volunteer at rest. Then measure all the variables again andrecord in the table.Analyze and Conclude:1. What is the independent variable in this experiment?2. Graph the relationship between the independent and dependent variables. You may choose line graphs or bargraphs. Make sure to give each graph a title, label the axes (and include a unit) and use an appropriate scale.Please color code and provide a key.

3. In general, what type of relationship (direct or indirect) is shown between the duration of exercise and each ofthe dependent variables?4. How does this lab illustrate a negative feedback loop?

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