Exercise 15 - External Respiration

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External RespirationDOMINGO,GALOS,GENUINO,HILVANO,LAPIRA,LOZANO

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Abstract

The rate of breathing, being a function of metabolic activity of an

organism, is under control by the brain’s medulla oblongata, which

in turn, is affected by the blood’s pH. As the CO2 concentration in

the blood increases, it becomes slightly acidic.

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Abstract

The purpose of this experiment is to clarify the relationship of the breathing

rate with the CO2 concentration. To show this relationship, we expose a test

subject to various situations of alteration of temperature, and letting the

subject expend energy. These various alterations will vary the amount of CO2

present inside the organism, thus stimulating a change in breathing phase. As

a conclusion to the experiment, temperature is directly proportional to the

breathing rate and a subject exposed to strenuous activity will most likely

expend more of the product formed in its system’s metabolic processes, thus

increasing breathing rate.

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Abstract

The experiment has shown that increase in temperature will hasten chemical

processes which in turn increase the amount of CO2 in the system, thus

increasing the organism’s breathing rate. On the other hand, decreasing the

temperature slows down metabolc processes and thus decreases the

breathing rate. Also, a subject exposed to strenuous activity will show

increase in breathing rate because it expended more of the product formed

in the metabolic processes. These results imply that the breathing rate is

directly proportional to the concentration of CO2 inside the system.

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I. Introduction

One of the requirements for the production of ATP in animals is

the presence of fresh oxygen in the body. Terrestrial animals fulfill

this requirement through a process called external respiration, more

commonly known as breathing. Air from the environment is taken in

the body, and is sent through respiratory structures.

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I. Introduction

It is brought into contact with respiratory membranes, where the

required oxygen is transmitted into the bloodstream. Waste gases,

such as carbon dioxide, are expelled from the body through these

respiratory structures as well.

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I. Introduction

In most terrestrial animals, external

respiration starts with the flattening of the

diaphragm. The suction effect this has allows

air to enter the respiratory system. It first

passes into the nasal cavity, where the air is

filtered for dirt and other unwanted solids. It

then passes through the pharynx, and enters

the larynx when the glottis opens to allow air

through.

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I. Introduction

Air then passes through the trachea, the bronchi, the bronchial

tubes, and finally the bronchioles, where the alveoli facilitate the

transfer of gases into and out of the bloodstream. The relaxation of

the diaphragm then allows the waste gases to be expelled into the

environment.

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I. Introduction

Because the production of ATP highly depends

on external respiration, the rate at which one

performs external respiration is affected by the

amount of metabolic activity in the body.

Strenuous activities, such as running, causes the

body to breath faster in order to accommodate

the large demand of ATP. When one is sleepy, the

body induces yawning in order to gather the ATP

necessary to stay awake; when one sleeps, the

rate of breathing becomes slower (though not by

a significant amount.)

10In this exercise, the group’s objectives

were to:

measure the breathing rate of an individual

relate the breathing rate to the amount of carbon dioxide produced

determine how exercise affects breathing rate

determine how temperature affects breathing rate

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Objectives

Objectives 1 – 3 were fulfilled by comparing the relative rates

of breathing after performing different physical activities.

Objective 4 was completed by comparing the relative rates

of breathing of a goldfish in different thermal conditions.

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II. Methodology

Part 1

Effect of Physical

Activity on Breathing

Rate

100 ml of lime water (saturated calcium

hydroxide in water) was poured into a 125-

ml capacity Erlenmeyer flask, making sure

to slowly dilute the flask with water while

shaking when the solution was too cloudy.

A drinking straw was inserted into the flask.

The lime solution was blown into, breathing

normally. Changes were observed as the

clear solution became cloudy.

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II. Methodology

Part 1

Effect of Physical

Activity on Breathing

Rate

The number of breaths in one minute after

a student had performed the following

exercises was counted by his/her partner.

Normal, unforced breathing while sitting

down

Unforced breathing while sitting down

after 100 jumping jacks

Unforced breathing while sitting down

after holding one's breath for as long as

possible.

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II. Methodology

Part 1

Effect of Physical

Activity on Breathing

Rate

The preceding exercises were

repeated. This time, a flask of

limewater (100 ml) was blown into by

the student performing the

exercises, and the time it took for the

clear solution to turn cloudy was

recorded. The count was stopped the

moment the solution began to

change.

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II. Methodology

Part 2

Effect of

Temperature on

Breathing Rate

A jar was filled with a sufficient

amount of dechlorinated water, and

a fish was placed in it. The

temperature of the water was

measured with a thermometer.

The aquatic breathing rate of the fish

was determined by counting the

number of times the operculum

opens and closes in one time.

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II. Methodology

Part 2

Effect of

Temperature on

Breathing Rate

The jar containing the fish was

transferred and immersed in an ice

bath. The temperature of the water

in the jar and the aquatic breathing

rate of the fish were determined.

The jar was removed from the ice

bath and the temperature was

allowed to return to room

temperature.

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II. Methodology

Part 2

Effect of

Temperature on

Breathing Rate

The jar was placed in a warm water

bath (about 37 degrees Celsius.) The

temperature of the water and the

breathing rate of the fish were

determined.

18III. Results and Discussion (Physical

Activity)

The data obtained from the exercise is tabulated below.

Activity Breathing Rate Minimum Time for Lime

Sitting 13 breaths/min 31 seconds

After exercise 29 breaths/min 21 seconds

Holding breath 16 breaths/min 25 seconds

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1. Explain what happened to the clear

solution of CaOH after one had blown air

into it. Show the chemical equation.

The solution of lime water began to turn murky white after it was

breathed into a few times.

The chemical reaction that occurred is as follows:

Ca(OH)2 + CO2 → CaCO3 + H2

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1. Explain what happened to the clear

solution of CaOH after one had blown air

into it. Show the chemical equation.

The calcium hydroxide in the lime water solution reacted with the

carbon dioxide that came from the expiration of air from the lungs of

the student who breathed into the flask. The results were water, and

calcium carbonate; it was the presence of calcium carbonate in the

solution that turned it murky white.

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2. What does the above procedure mean,

is it accurate?

The procedure above was meant to measure the rate of external

respiration of a person after different physical activities of increasing

degree of stress on the body.

Although the experiment can yield relatively accurate results

qualitatively, there are a few factors that limit the credibility of the results:

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2. What does the above procedure mean,

is it accurate?

The first is that the student performing the exercises was aware of

the experiment. Our normal rate of breathing, relaxed or after

exercise, is mostly involuntary. When one is aware of his/her

breathing, he/she cannot be expected to exhibit his/her normal rate

of breathing. This affects the results greatly.

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2. What does the above procedure mean,

is it accurate?

The second is that the results will differ between people. People

who are relatively healthy will not exhibit a change in breathing as

drastic as those who are not physically active after exercise.

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3. What relationship exists between

breathing rate and activity performed by

the student?

As the physical activity performed became more relatively taxing

on the body, the breathing rate increased.

The breathing rate after holding one's breath was not

significantly greater than normal; the difference in breathing rate was

very large, however, after the one hundred jumping jacks.

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4. What relationship exists between the rate

of change in the solution and the activity

performed by the student?

The rate of change of color of the solution increased with the

relative difficulty of the exercise.

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4. What relationship exists between the two

sets of data?

The data shows that the difficulty of the physical activity, breathing rate, and rate of change of

color of the solution are proportional to each other.

As the body increases its metabolic and systemic output to accommodate the student's

strenuous activity, the rate of consumption of ATP increases. The body expels CO2 at a faster rate

as a result; this caused the increase in rate of change of color of the lime water solution. The

increased demand of O2 and the increased amount of expelled CO2 also demanded a faster rate of

breathing.

27III. Results and Discussion

(Temperature)

The data obtained from the exercise is tabulated below.

Activity Temperature 1st 2nd 3rd

Room

Temperature

23o C 104 100 110

Cold Water

Bath

20o C 89 84 87

Warm Water

Bath

37o C 158 128 149

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1. Based on your tabulated data, how does

temperature affect the breathing rate of

an organism? Explain.

As a general trend, the breathing rate

of the goldfish decreases with

temperature.

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1. Based on your tabulated data, how does

temperature affect the breathing rate of

an organism? Explain.

Because goldfish are cold-blooded animals, their biological processes are under the

control of external forces (the temperature.) Most chemical processes occur faster at

higher temperatures than they do at lower ones, especially the ones dealing with

metabolization. In this case, the goldfish are metabolizing their food at a faster rate at

higher temperature, so need to respire faster. They are also far more active at the higher

temperature, again, because they can metabolize their food faster.

302. The fish is a poikilotherm. Would a

relatively small increase in the temperature

have as much effect on the breathing rate

of a homeotherm? Explain.

The small increase in temperature would not have as much

effect on the breathing rate of a homeotherm, or warm-blooded,

organism. Homeothermy is internal thermoregulation regardless of

external influence; as such metabolic activity inside a warm-blooded

organism such as a human will continue at a relatively constant rate

regardless of temperature. Thus respiration will not increase or

decrease drastically because of changes in temperature.

Poikilotherm- an organism that

cannot regulate its

body temperature

except by behavioral

means

Homeotherm- an organism that can

regulate its body

temperature by

metabolic means

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IV. Conclusion

The production of ATP in organisms is highly dependent on the external

respiration of the organism. Thus, the rate of respiration in an animal is

greatly affected by many environmental factors. As a useful rule of the

thumb: as metabolic activity in an animal increases, the required external

respiration in order to maintain that metabolic activity increases.

Environmental factors that affect the rate of respiration are the difficulty of

physical activity, and the external temperature (for poikilotherm.)

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References

Biology 10 (General Biology) Laboratory Manual. Department of Biology - College of Arts and

Sciences - University of the Philippines, Manila. Print.

Campbell, N.A., Reece, J.B. & Meyers, N. (2006). Biology. Frenchs Forest: Pearson

Education.

Delos Reyes, J. (2006). Introduction to Biology: Principles and Processes (6th ed.). Department of

Biology, College of Arts and Sciences, University of the Philippines Manila.

Klein, David R. (2012). Organic Chemistry. United States of America: John Wiley & Sons, Inc.