Experiment 4 measured lung volumes and capacities in a class. Males had larger inspiratory reserve volumes, expiratory reserve volumes, and vital capacities than females due to differences in thoracic cavity size. Experiment 5 examined changes in respiration during breath holding, rapid breathing, and exercise. Breath holding lowered tidal volume and ventilation while rapid breathing increased them. Exercise caused the greatest increases in tidal volume, respiratory rate, and ventilation. Breathing into a paper bag can help anxious patients by increasing exhaled carbon dioxide levels. Giving supplemental oxygen to patients with emphysema may help balance their oxygen and carbon dioxide drive if they are oxygen dependent. Pure oxygen does not help the air hunger felt by athletes after a race due to lactic acid
2. Experiment 4: Data
Table 1
Class average Class average
Volume measurement
Individual (L) (Male) (Female)
(L)
(L) (L)
Tidal Volume (TV) .2 .2 .2
Inspiratory Reserve (IRV) .2 .5 .2
Expiratory Reserve .3 .4 .3
(ERV)
Vital Capacity (VC) .4 1.1 .4
Residual Volume (RV) ≈1.5 ≈1.5 ≈1.5
Total Lung Capacity 2.6 2.6 2.6
(TLC)
3. Experiment 4: Analysis
1) What was your Tidal Volume (TV)? What would you expect your TV to
be if you inhaled a foreign object which completely obstructed your
right mainstream bronchus?
My tidal volume was .02, if I were to completely obstruct my right
mainstream bronchus it would cut the TV in half, to .1.
2) Describe the difference between lung volumes for males and females.
What might account for this?
The only differences in our class averages were in the IRV, ERV, and
the VC. This is because of the size difference in male and female
thoracic cavity dimensions. The males who did it and had a cavity
size closer to the females who performed the experiment had less
differences in their data.
3) Calculate your Minute Volume at rest. If you are taking shallow
breaths (TV = 0.20 L) to avoid severe pain from rib fractures, what
respiratory rate will be required to achieve the same minute volume?
.02 x 14 = 2.8, a person taking shallow breathes breathing rate
would increase to compensate for the decrease in TV.
4. Experiment 4: Analysis Cont.
4) Exposure to occupational hazards such as coal dust, silica dust,
and asbestos may lead to fibrosis, or scarring of lung tissue. With
this condition, the lungs become stiff and have more “recoil.”
What would happen to TLC and VC under these conditions?
They would both decrease because the lungs aren’t able
to properly expand, therefore their breathing rate would
increase to compensate.
5) In severe emphysema there is destruction of lung tissue and
reduced recoil. What would you expect to happen to TLC and VC?
The TLC would remain the same because the RV increases due
to extra air extra air left in the person’s lungs while the VC
would decrease because the person is unable to properly
exhale the air in their lungs.
6) What would you expect to happen to your Expiratory Reserve
Volume when you are treading water in a lake?
It would increase due to the strain of treading water because
body has an increased need for oxygen. This causes the
breathing rate to increase causing the person’s exhales to be
increasingly powerful.
7. Experiment 5: Analysis
1) Describe the changes in respiratory rates, tidal volumes, and minute
ventilations that occurred after each of the following physiologic
challenges in terms of CO2 levels and their effect on respiratory drive:
(a)breath holding – After holding your breath the tidal
volume, respiratory rate, and minute ventilation was lower than it
was before.
(b)rapid breathing – After rapid breathing the tidal volume,
respiratory rate, and minute ventilation was higher than it was
before with normal breathing.
(c) exercise – After exercise the tidal volume, respiratory rate, and
minute ventilation increase and was higher than before without the
exercise.
2) Which challenge caused the greatest change in respiratory rate (pre-
challenge vs. post challenge)? Tidal volume? Minute ventilation? Did
respiratory rate or tidal volume change the most relative to its resting
value?
The greatest change in respiratory rate was when he was rapid
breathing. The greatest change in tidal volume was holding breath.
And the greatest change in minute ventilation was rapid breathing.
The tidal volume changed the most from what its resting value was.
8. Experiment 5: Analysis Cont.
3) How might breathing into a paper bag help someone who is extremely
anxious and hyperventilating?
Breathing into a paper bag can help someone who is anxious and
hyperventilating because when they breathe into the bag and exhale
into the bag the levels of CO2 are increased in the bag, and it helps
bring more CO2 into the body and bloodstream and make your PH
normal.
4) Some patients with severe emphysema have constant high levels of CO2
because of inadequate ventilation. The central nervous system breathing
center in these patients becomes insensitive to CO2 and more dependent on
the level of O2, which is low. These patients are said to have “oxygen-
dependent respiratory drive.” What might happen if you give such a person
high levels of supplemental O2?
If you give them high levels of O2 it should help balance out the need
for both CO2 and O2, making the oxygen-dependent state slowly go
away.
5) Would breathing pure O2 help the air hunger experienced by athletes who
have just completed a race? Why or why not?
Breathing pure O2 after a race doesn’t help athletes any more than just
breathing the regular air afterwards. They are feeling the air hunger
because of the overuse of their muscles causing a buildup of lactic acid
in the muscles and blood.
