Observing the role of homeostasis in the body after exercise Biology (T): Functioning Organisms Biology Practical Report 0383210 Mrs Woinarski Due 14th November 2012 Introduction: Homeostasis plays a vital role in the maintenance of a normal environment in which bodily systems are able to function most efficiently. The importance of homeostasis can be seen in blood pressure and pulse rate, as measurements which are not in the normal range can create serious health problems. Exercise has a known effect on both of these systems, as it results in a rise in body temperature and dilation of blood vessels, as well as an increase in breathing rate.

By measuring how these rates return to normal levels after exercise demonstrates homeostasis in the body, and helps to describe the ways in which the endocrine system and organs involved impact this. Aim: To demonstrate the role of homeostasis in reaching normal levels for pulse rate and blood pressure after an increase due to exercise and investigate which of the relative feedback systems works faster to achieve homeostasis. Apparatus: Stopwatch 1. 5m Skipping Rope Electric blood pressure monitor Method:

Using the electric blood pressure monitor, both blood pressure and pluse rate were measured at a resting level for the first participant. In an open area, participant was asked to skip 100 times using rope, without any break. Immediately afterwards, the stopwatch was set and the blood pressure and pulse rate of the participant were measured using the blood pressure monitor and recorded. Using the stopwatch to see time after exercise, blood pressure and pulse rates were measured again at t=1, t=5 and t=10, where t equals minutes after exercising.

The entire process was completed on each participant individually. Results: Raw Data Table 1: Results for Participant 1 Time (t) |Pulse rate (bpm) |Blood pressure (mmHg) | |-1 |88 |105/67 | |0 |140 |135/119 | |1 |128 |138/69 | |5 |108 |113/63 | |10 |96 |109/66 | | Table 2: Results for Participant 2 Time (t) |Pulse rate (bpm) |Blood pressure (mmHg) | |-1 |90 |100/70 | |0 |150 |130/100 | |1 |120 |120/82 | |5 |100 |112/75 | |10 |93 |103/70 | | Table 3: Results for Participant 3

Time (t) |Pulse rate (bpm) |Blood pressure (mmHg) | |-1 |81 |112/68 | |0 |100 |120/93 | |1 |95 |117/90 | |5 |91 |113/81 | |10 |80 |110/69 | | Table 4: Results for Participant 4 Time (t) |Pulse rate (bpm) |Blood pressure (mmHg) | |-1 |92 |126/79 | |0 |92 |154/65 | |1 |92 |143/67 | |5 |92 |131/60 | |10 |92 |125/71 | | Table 5: Results for Participant 5 Time (t) |Pulse rate (bpm) |Blood pressure (mmHg) | |-1 |86 |80/55 | |0 |90 |85/67 | |1 |89 |85/67 | |5 |87 |83/68 | |10 |83 |79/53 | |Processed Data Discussion:

The results of this experiment effectively demonstrate the role of homeostasis in returning both pulse rate and blood pressure to normal rates after exercising, as can be seen in the trends in the data provided. As seen in graphs 1, 2 and 3 the trend was a peak in both blood pressure and pulse rate immediately after exercise, followed by a slower decrease to normal levels. Pulse rate, as seen in graph 1, changed quite dramatically in participants 1 and 2 after exercise, and although this same peak is not so obvious in participants 3 and 5, they show a similar pattern.

The difference in scale of change here could be affected by many uncontrollable variables, such as the participants’ fitness levels. However, by comparing each participant’s results to their resting levels, an accurate description can be made. Participant 4 is, in this case, an anomaly, as exercise did not have any effect on their pulse rate (Table 4). Graphs 2 and 3 show the participants’ change in blood pressure as a result of exercise, separated into systolic and diastolic blood pressure measurements.

Again, a peak can be seen immediately after exercise as blood is being forced throughout the body to supply nutrients to muscles which have just been used, shown in both systolic and diastolic rates. Blood pressure returns to normal through a homeostatic process after exercise, as a result in the changing size of blood vessels. After blood pressure had returned to normal, in the majority of participants, it then in fact continued to decrease slightly before creating a new resting level. This is a result of the dilation of blood vessels, which then move more easily through arteries. Conclusion:

In conclusion, the process of homeostasis in returning to normal levels of blood pressure and pulse rate after exercise have effectively been demonstrated. The different speeds at which these homeostatic processes are completed are a result of the endocrine feedback systems involved. Sources of error in the experiment are the limited results obtained as a result of time constraints. For a more accurate outcome, more participants should be tested so that any anomalies can be disregarded, and each participant should be tested multiple times to obtain average results as a way to avoid any mechanical errors.

As the same device was used to test the blood pressure and pulse rate of each participant, mechanical error was reduced, however multiple tests would have improved the results. Bibliography: ‘Homeostatic mechanisms’ 2012, WestAustralian Government, viewed 10 November at http://tle. westone. wa. gov. au/content/file/ea6e15c5-fe5e-78a3-fd79-83474fe5d808/1/hum_bio_Science_3a. zip/content/003_homeostasis/page_05. htm Hardy, Richard N. 1983, Homeostasis, 2nd ed, Edward Arnold, London ----------------------- [pic] [pic] [pic]