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Title: Homeostasis: the effect of exercise intensity
Description: Homeostasis: the effect of exercise intensity This is an A+ assesment I scored really high for it IB Biology Internal Assessment
Description: Homeostasis: the effect of exercise intensity This is an A+ assesment I scored really high for it IB Biology Internal Assessment
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IB Biology Internal
Assessment
Homeostasis: the effect of exercise intensity
Research Question:
How does physical exercise at intensities of 120, 140, 160, 180 punches per minute (ppm)
affect homeostatic controls with regard to rate of CO2 expulsion (s-‐1), blood pressure
(mmHg), vasodilation, sweat and breathing rate?
Aim:
To investigate the effect of physical activities at different intensities (ppm) on homeostatic
controls in maintaining the rate of CO2 expulsion (s-‐1), blood pressure (mmHg), vasodilation,
sweat and breathing rate within certain limits
...
In effect,
maintaining an internal environment in which controlled variables are kept within certain
limits is known as homeostasis
...
180)
...
Physical activity is dependent
upon the use of skeletal muscle for movement and exercise
...
In cellular respiration, oxygen (O2) is the reactant and carbon dioxide
(CO2) is the product
...
To ensure the transport of O2 to cells, and ultimately, to remove CO2 from the
body, certain mechanisms are undertaken by the body
...
632)
...
632)
...
This
factor can be qualitatively observed by looking at the breathing rate
...
With the increase in respiratory gases moving into and out of cells, blood which transports
these must as well circulate faster within the body
...
The signal is then reached to the sinoatrial node (SA node) which consequently sends signals
to the atria in order to increase the rate of their contraction
...
Overall, these processes result in an increased heart rate and hence an increased flow of
blood through the arteries (Damon, 2007, p
...
Due to this increase in flow, high
pressures of blood enter the arteries ready to carry the respiratory gases at a faster speed
...
In addition, due to cellular respiration, heat is also a product and therefore, the body
temperature begins to rise during exercise
...
181)
...
Hypothesis:
As explained earlier, as the intensity of exercise increases, there is a higher demand for the
supply of O2 to the cells and subsequently a higher need to expel CO2 from the body
...
The primary two functions that do so are the buffer systems and the increase in
the ventilation rate
...
This increase in blood flow and pressure in the
arteries is blood pressure; hence an increase in intensity would result in an increase in blood
pressure
...
Also, due to an increase in ventilation rate, the
breathing rate is also expected to increase
...
Variables:
Independent:
•
Physical exercise at intensities of 120, 140, 160, 180 punches per minute (ppm):
Intensity variations (ppm) will be the basis of the experiment that should cause a change in
the rate of CO2 expulsion (s-‐1) and blood pressure (mmHg)
...
With the increase of
intensities it hypothesised that there will also be an increase in the rate of CO2 expulsion
and blood pressure
...
Dependent:
•
Carbon Dioxide (CO2) expulsion (s)
As a result of increased intensities, there will be an increased rate of CO2 expulsion as was
explained earlier
...
First, it should be noted that the
rate of CO2 expulsion will be measured qualitatively by observing the change in colour of a
Page 3 of 28
solution which is caused by the change in pH
...
e
...
The time will then be converted into a rate
...
With the increase in intensity, higher pressures of blood will be circulating the
body
...
These two variables will be
measured using a blood pressure monitor
...
In order to release
some of the inner temperature from the body, blood vessels dilate and are therefore closer
to the outer environment
...
This is evident when the face of the
subject is slightly red
...
•
Sweat:
Another way of maintaining a stable internal temperature is by the means of sweating
...
This is will also be qualitatively measured
...
This is will be qualitatively measured by looking at the level of
panting and breathing rate
...
5˚C):
The temperature of the solution and the outer environment must remain constant in
order to obtain fair and consistent results
...
5˚C) since temperatures affect molecular collisions and therefore affect the rate
of reaction
...
•
Volume of solution (water) and volume of indicator:
The volume of water and indicator must remain constant throughout the different
trials and intensities to obtain consistent results
...
A
difference in the amount of water will also lead to different amounts of hydrogen
carbonates being formed in the solution, hence affecting the pH
...
•
Decrease in pH
The pH of the solution will be measured using a pH meter
...
e
...
Therefore it is important to stop the time after
this change to obtain results that are fair and consistent throughout the experiment
...
This is essential to obtaining accurate
qualitative data
...
g
...
Also because having a
different BMI may cause different responses
...
Therefore in order to maintain
consistent results throughout the experiment, the subject cannot be changed during
Page 5 of 28
the experiment
...
Another important
factor that needs to be controlled is the position of the subject when taking blood
pressure
...
Also, the same blood pressure monitor must be used to
obtain consistent results
...
Control:
The control will involve setting up a conical flask with water containing five drops of
universal indicator
...
If there
is not, then it can be said that the CO2 reaction with water to form carbonic acid is the cause
of the colour change
...
0 L water
•
striking pad
•
stopwatch
•
pH meter
•
0-‐100˚C Thermometer
•
Microlife blood pressure monitor
Safety
•
Ensure that the subject is able to conduct the exercise
...
Page 6 of 28
Method for Data Collection:
Control
•
Set up the control by measuring 100ml of water using the measuring cylinder
...
•
Add 5 drops of universal indicator (the solution should be greenish in colour)
•
Use the pH meter to test the pH of the solution (should be neutral, i
...
close to 7)
...
The colour of the solution
should not change
...
Try to have an assistant to help in data collection
...
Ensure that the
subject is sitting down, does not move or speak, and is calm during the test
...
Table 1: The effect of physical exercise at different intensities (ppm) on systolic and
diastolic blood pressures (mmHg)
Intensity of Exercise (ppm)
Blood Pressure (mmHg) ± 1
Trial 2
Trial 1
Trial 3
SBP
DBP
SBP
DBP
SBP
DBP
Resting
120
140
160
180
2
...
Once again, pour it into the conical flask and add 5 drops of the universal
indicator
...
Use the 0-‐100˚C
Page 7 of 28
thermometer to ensure that the temperature is consistent throughout the
experiment
...
3
...
Also, be
ready to observe the levels of sweat, vasodilation and breathing rate
...
Diagram 1: Observations in relation to the rate of colour change of the solution from
green to yellow at different intensities of exercise (ppm)
...
Key 1:
No change in the
colour of the solufon
Key 2:
Rate of colour change
is relafvely fast
Key 3:
Rate of colour change
is slighfng faster than
key 2
...
Assign a key from 1-‐5 to represent the level of sweat at different intensifes
...
Assign a key from 1-‐5 to represent the breathing rate at different intensifes
...
Diagram 4: Observations in relation to the level of vasodilation at different intensities of
exercise (ppm)
...
Key 1:
No sign of vasodilafon
Key 2:
Opaque red areas
becoming slightly visible
Key 4:
Vasodilafon is clearly
higher with an increase
in redness of cheeks
...
Quantitatively, be ready to measure the time it takes for the pH of the solution to
drop by one unit, immediately stop timing after so
...
Get ready to time using the stopwatch
...
Start timing as soon as the
breathing begins
...
Record the quantitative
data in table 2
...
Table 2: The effect of physical exercise at different intensities (ppm) on time taken for pH
to decrease by one unit (s) as a result of CO2 expulsion into the flask
Time (s) ± 0
...
Repeat steps 1-‐4 for the next two trials; record the data
...
Obtain another conical flask and use the measuring cylinder to measure 100ml of
water
...
Make sure the pH meter is also in the solution
...
Proceed to collect data for the intensity at 120 punches per minute (ppm)
...
Let one
hold the striking and another responsible for timing and counting the punches
...
The assistant timing and
counting can help maintain the consistency by informing the subject when to speed
up or to slow down
...
Start punching and importantly, timing for a minute
...
Observe the rate of colour change (qualitative) and
assign a key from diagram 1
...
9
...
e
...
Proceed to use the blood pressure monitor to measure the blood pressure of the
subject
...
Compare these results with the following
reference chart showing the ranges for blood pressure:
Reference: (Modric, 2009)
11
...
This should be consistent throughout the experiment
...
Repeat steps 6-‐11 for the next two trials
...
Repeat steps6-‐11 for the remaining intensities of 140, 160 and 180 (ppm), each for
three trials
...
Page 11 of 28
Method for Data Processing
When processing your data, you will need to find the averages of the following:
•
The time taken for the pH of the solution to decrease by one unit in seconds
...
Also, the time taken for the pH to decrease by one unit should be converted into rate (s-‐1),
and this is done by dividing 1 by the average time taken
...
In addition, the percentage uncertainty should be calculated to account for possible
uncertainties that may have risen
...
Note that the apparatus used for the calculations regarding CO2 expulsion (s-‐
1
) involve the stop watch and the measuring cylinder
...
As for the blood pressure, the only uncertainty is that of the monitoring device
...
To do this, you divide the
uncertainty of certain equipment used that may have affected your results by the data you
!"#$%&'("&)
have collected and then times it by 100 ( 𝒑𝒆𝒓𝒄𝒆𝒏𝒕𝒂𝒈𝒆 𝒖𝒏𝒄𝒆𝒓𝒕𝒂𝒊𝒏𝒕𝒚 = !"#" !"#$!%"% ×100)
...
This can
then be converted to a total absolute uncertainty by multiplying the rate of CO2 or blood
pressure by the total percentage uncertainty
...
In these graphs, the independent should be the x-‐axis (the different intensities)
while the dependent should be the y-‐axis (the blood pressure or rate of CO2 expulsion)
...
On the other hand, the diastolic blood pressure
(DBP) is only slightly changed – sometimes values increase and sometimes decrease
...
Page 14 of 28
Table 2: The effect of physical exercise at different intensities (ppm) on time taken for pH to
decrease by one unit (s) as a result of CO2 expulsion into the flask
Intensity of Exercise (ppm)
Trial 1
Time (s) ± 0
...
15
25
...
25
120
20
...
12
20
...
68
19
...
45
160
17
...
21
17
...
12
14
...
17
Evidently, the time taken for the pH to drop by one unit decreases as the intensity of the
exercise increases
...
ResNng Phase:
Rate of colour change
is relafvely fast
120 (ppm):
Rate of colour change
is slighfng faster than
key 2
...
Figure 1: The colour of the solution prior to the CO2 exhalation into the flask (green):
Using the pH chart, the pH of this solution is 7
...
Diagram 2: Observations in relation to the level of sweat at different intensities of exercise (ppm)
...
The sweat was observed to be on the neck, face, and other areas,
suggesting that with increased intensity, the level of sweat increases
...
ResXng Phase:
Normal breathing rate
120 (ppm):
Breathing rate
increased slightly
140 (ppm):
Breathing rate faster
than the previous
160 (ppm):
Breathing rate is
evidently faster with an
increase in panfng
180 (ppm):
Fastest breathing rate,
panfng faster than
previous intensifes
...
Page 16 of 28
Diagram 4: Observations in relation to the level of vasodilation at different intensities of exercise
(ppm)
...
180 (ppm):
The highest visibility of
vasodilafon and clearly
more than previous
intensifes
...
The uncertainties of this experiment are shown in the table below:
Apparatus
Uncertainty
Stop watch
± 0
...
Page 17 of 28
Data Processing
The following data processing will involve averaging data
...
e
...
Table 3: The average of systolic and diastolic blood pressures (mmHg) at different intensities
(ppm)
Blood Pressure (mmHg) ± 1
Trial 1
SBP
DBP
Trial 2
SBP
DBP
Trial 3
SBP
DBP
Average
SBP
DBP
129
79
131
68
126
71
129
73
120
135
81
131
69
123
72
130
74
140
139
73
137
77
140
67
139
72
160
149
78
152
73
147
74
149
75
180
164
69
167
72
172
68
168
70
Intensity of
Exercise (ppm)
Resting
Calculating an average of three trails helps provide fair results and therefore will be used for
the rest of the experiment
...
Table 4: Averages of the time taken for pH to decrease by one unit (s) and the rate of CO2
expulsion (s-‐1)
...
01
Intensity of
Exercise (ppm)
Trial 1
Trial 2
Trial 3
Average
Rate of CO2
expulsion (s-‐1)
Resting
23
...
66
25
...
69
0
...
82
19
...
79
20
...
04941
140
18
...
07
18
...
73
0
...
44
17
...
11
17
...
05797
180
16
...
78
16
...
69
0
...
These were rounded to four significant figures
...
Page 18 of 28
Using the uncertainties of the apparatuses (stop watch and measuring cylinder) the
percentage uncertainty can be found
...
01 and the
uncertainty of the measuring cylinder is ±1
...
!
...
Note the use of
100ml because this amount was used for all trials and intensities
...
01
Percentage
uncertainty of
Stop watch (%)
Percentage uncertainty of
Measuring cylinder (%)
Resting
24
...
04050
1
120
20
...
04941
1
140
18
...
05339
1
160
17
...
05797
1
180
15
...
06373
1
This table consists of the percentage uncertainties that may have evolved during the
experiment
...
The total percentage uncertainty will now be calculated by adding the percentage
uncertainty of the stop watch and the measuring cylinder
...
Page 19 of 28
Table 6: Total percentage uncertainty and total absolute uncertainty of the time taken for pH to
decrease by one unit (s) as a result of CO2 expulsion into the flask
...
04050
0
...
041
0
...
041% = 0
...
04941
0
...
049
0
...
049% = 0
...
05339
0
...
053
0
...
053% = 0
...
05797
0
...
058
0
...
058% = 0
...
06373× 1
...
0006779
The absolute uncertainty accounts for all possible errors
...
06373
0
...
064
the same unit as the rate of CO2 expulsion (s-‐1)
...
04050 ± 0
...
04941 ± 0
...
05339 ± 0
...
05797 ± 0
...
06373 ± 0
...
Note: the uncertainty of the
blood pressure monitor is ± 1 mmHg
...
Absolute uncertainty will
be calculated by multiplying the blood pressure by the percentage uncertainty
...
7752
1
...
7692
1
...
7194
1
...
6711
1
...
5952
1
...
Noticeable is the fact that the absolute uncertainty is one which is the same as the
uncertainty of the blood pressure monitor
...
The x-‐axis will be
independent variable (intensity) while the y-‐axis will be the dependent variable
...
From the graph it can be seen that as the intensity of exercise increase, the rate of CO2
expulsion also increases
...
Also, error bars have been
included to account for the total absolute uncertainty values (table 7)
...
Page 22 of 28
Graph 2: The effect of physical exercise at different intensities (ppm) on the systolic and diastolic
blood pressure (mmHg)
Evidently from the graph it can be seen that the systolic blood pressure increases as
intensity of exercise increases
...
This suggests that diastolic blood
pressure does not follow trend of the systolic blood pressure
...
For
example, the fact that as intensity of exercise increases, the rate of carbon dioxide
exhalation increases supports the hypothesis
...
This is evident when comparing the
intensities of 160 (ppm) and 180 (ppm), the former with a rate of CO2 expulsion of 0
...
06373 (s-‐1)
...
Moreover, the hypothesis that the
systolic blood pressure increases as a result of increased intensity was evidently true
throughout the experiment
...
Again, from these values it can be seen
that with an increased intensity there will be an increase in the systolic blood pressure
...
For example, at 120 (ppm) the diastolic blood pressure was 74 (mmHg), but at
the intensity of 140 (ppm), the blood pressure in fact decreased to 72 (mmHg)
...
However with the increase of exercise intensities, these factors also
increase and the body then responds by dilating the arteries
...
Therefore, the hypothesis was
only partly supported as it was earlier hypothesised that the diastolic blood pressure would
increase, but this was not the case
...
With an increase in exercise, these measurements of homeostasis
increased
...
Therefore, though the experimental
results do not completely support the hypothesis, specifically the hypothesis regarding an
Page 24 of 28
increase in diastolic blood pressure, they do support the variables – namely, the increase in
the rate of CO2 expulsion, systolic blood pressure, sweat, vasodilation and breathing rate
...
The first limitation is in relation to the breathing rate/intensity when exhaling into
the straw and hence into the flask
...
Also, the intensity of breathing
into the straw may have also affected the results obtained
...
This would have affected the time required to drop the
pH by one unit and hence the results collected for the rate of CO2 expulsion
...
After so, the change in pH can be examined rather than it being
controlled
...
Another source if error is the possibility that the CO2 exhaled into the flask might not have
completely reacted in water to produce hydrogen carbonate
...
This bubbling might have
contained undissolved carbon dioxide gases, hence affecting the pH of the solution
...
To overcome this source of error, other direct mechanisms of the
homeostatic controls can be measured such as breathing rate, heart rate, and others
...
Another limitation and a source of error is the fact that the blood pressure is not
immediately taken, rather it is taken after exhaling into the conical flask
...
This systematic error is significant as it may lower the blood pressure as a result of
delayed measurement of the blood pressure
...
To overcome this
problem, an instantaneous blood pressure monitor can be used immediately after the
subject completes the exercise
...
Another way to overcome the limitations
relating to measuring blood pressure is to measure direct homeostatic controls
...
Therefore direct measurements of homeostasis may be utilised, as explained
earlier, for example, measuring heart rate, breathing rate, among others
...
A third source of error relates to measuring the punches per minute
...
The subject might punch at a fast rate at
the beginning but then slow down later, and this will affect the levels of CO2 expulsion as
well as blood pressure
...
For example, using a treadmill to
run certain distances at a certain speeds
...
Therefore, it minimises
the amount of errors and allows for the collection of more accurate quantitative data such
as heart rate if the treadmill is equipped with a heart rate sensor
...
Stopwatches depend on human reaction times; therefore, the
assistant stopping the time might not stop as soon as the pH drops by one unit, especially
because the times obtained at different intensities where really close with one to four
seconds difference between each other
...
24 (s) while for the 140 (ppm) intensity, the time was 18
...
Evidently, there is a short time frame between these two intensities, and therefore the
longer an assistant takes to stop the time, the higher the effect on the accuracy of the
results
...
Another effective again involves the use of treadmills
...
This would
therefore minimise the errors involved with stopwatches
...
The measuring
cylinder used had an uncertainty of ±1 mL which may have affected the volume of the water
poured into the conical flask
...
This source of error (random error) however is not as
significant as the ones discussed earlier because it is not directly related to the
measurements regarding the rate of CO2 expulsion
...
The
uncertainties of these are not as high as the measuring cylinder and therefore, they are
more reliable when it comes to controlling the volume of water in the flask
...
Generally, to obtain fair and consistence results, an addition of the number of trials is
helpful
...
The repeated trials would minimise the random errors
that may have occurred in the experiment
...
But,
the hypothesis is not supported with regard to diastolic blood pressure because it was not
greatly affected by exercise at different intensities
...
Page 27 of 28
Bibliography
Damon, A
...
Higher Level Biology for the IB Diploma
...
Lunardoni, C
...
Why Does Diastolic Blood Pressure Stay the Same During Exercise?
Retrieved April 6, 2012, from Livestrong: http://www
...
com/article/79009-‐diastolic-‐
blood-‐pressure-‐stay-‐same/
Modric, J
...
What Is Normal Blood Pressure Range? Blood Pressure Chart
...
healthhype
...
html
Page 28 of 28
Title: Homeostasis: the effect of exercise intensity
Description: Homeostasis: the effect of exercise intensity This is an A+ assesment I scored really high for it IB Biology Internal Assessment
Description: Homeostasis: the effect of exercise intensity This is an A+ assesment I scored really high for it IB Biology Internal Assessment