W1 End of Week Assignment

Homeostasis

In week one, we are learning how the cells and systems work together to survive. One process in which these systems work together is called homeostasis. The body is responding to a stimulus and acting to keep the body working properly. These responses may be external or internal. The mechanism involves a stimuli, hormone response and a self-adjusting mechanism or feedback regulation. We will test our own body’s homeostasis looking at heart rate.

Materials:

· Timer/Stopwatch – you can use a cell phone

· Calculator

Part. I.

The goal of this assignment is to demonstrate what you learned about explaining the concept of homeostasis, explaining a specific feedback mechanism and summarizing the process of homeostasis.

For this assignment, you need to write a short explanation explaining the provided flow chart for homeostasis feedback and include all of the following:

· your own definition of homeostasis,

· use a flowchart to create a specific feedback loop in the maintenance of homeostasis,

· and a detailed explanation of one example of a negative feedback loop in the body (you may not use thermoregulation).

· Cite all references.

Figure 1 Flowchart Example

Part II.

Evaluate your own homeostasis by exploring your heart rate during exercise and during rest.

Overview: Homeostasis is about maintaining that internal normal or even state in the body systems. The circulatory system helps move essential nutrients throughout the body. The circulatory system has both positive and negative feedback loops. With muscle contractions, the muscle tissues require oxygen. The heart must accommodate for these increased contractions and send more oxygen. This increases the heart rate. Once the vigorous activity declines, the heart rate returns to resting or set point or normal range. The negative feedback loop is how the nervous system responds to a stimulus triggering the circulatory system to respond and return the body to the even state, homeostasis. In this activity, you will determine the resting heart rate or set point.

Procedure: Students will take their resting and active heart rate to determine the set point.

1. To get an average of your resting heart rate, count the number of heart beats/pulse for 15 seconds. You can use the artery at your wrist or on your neck. Find the heartbeat with two fingers not your thumb. Breathe normally.

2. Record the number of beats per second for 15 seconds in the provided data table.

3. Wait for 15 seconds

4. Again, count and record the number of beats for second for 15 seconds.

5. Wait for 15-30 seconds and then take one more reading of your heart rate for 15 seconds.

6. Now average the three different readings. To do this you will add of the three numbers of beats per 15/ seconds and divide by 3.

7. Now we will measure the heart rate after exercise.

8. Run in place or vigorously move your body for 90-120 seconds even if it is just arm raises.

Resting Heart Rate

Post -Exercise Heart Rate

American Heart Association Staff. (2021 Mar 9).
“Target heart rates chart.” AHA Healthy Living.

1.
Create a Graph to include in your lab report.

· Use the Math is fun website to make a graph of your heart rate.

· Choose from the Math is fun website, click on the data button. Next click on Graphic Index then scroll down to the “Make a Bar Graph, Line Graph or Pie chart” and click on that option.

Math is fun web site

· Title: Your name’s Heart Rate Before & After Exercise

· X: Trial

· Y: Heart rate (beats per 15 secs)

· Values: (these will be the numbers from the above tables)

· Labels: Avg. Resting, 0 min, 1 min, 2 min, 3 min, 4 min, 5 min

Analysis and Conclusions

1. What did you determine as the set point or your normal resting heart rate?

2. What factors might cause this normal resting heart rate to change?

3. Why might your resting heart rate be different from other members of our class?

4. Where on your graph does it indicate how the circulatory system is responding to maintain homeostasis? On your graph, explain what demonstrates homeostasis is reached?

5. How would the graph look different if it was demonstrating a positive feedback loop?

6. Convert the resting heart rate to the beats per minute to see how your heart rate compares to normal from the AHA’s Target Heart Chart.

___ Beats X 4 =
___ Beats X
60 sec =
__ beats

15 sec 60 secs 1min 1 min

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