Physiology 1 Respiratory Case Study
Name ________________________
Please read Chapter 17 and review Chapter 16 before you complete this case study.
Part I. Smoking seriously hurts your lungs:
1. Smoking damages the lungs' natural cleaning and repair system and traps cancer-causing chemicals in
the lungs. Smoking destroys the tiny hairs (cilia), which line the upper airways and protect against
infection. Normally, there is a thin layer of mucous and thousands of these cilia lining the insides of your
breathing tubes. The mucous traps the little bits of dirt and pollution one breathes in, and the cilia move
together like a wave to push the dirt-filled mucous out of the lungs. Then one coughs, swallows, or spits
up the mucous, and the dirt is out of the lungs. When the lungs' natural cleaning and repair system is
damaged, germs, dirt and chemicals from cigarette smoke stay inside the lungs. This puts smokers at risk
for chronic cough, chest infections, lung cancer and COPD. Learn more about what's in cigarettes.
2. Smoking permanently damages the alveoli (air sacs) in the lungs and causes emphysema, making it
hard to breathe. The alveoli, little air sacs at the tips of your lungs, are built like tiny, stretchy balloons.
As we breathe in, the alveoli help us absorb oxygen into our body, and as we breathe out, alveoli help get
rid of the waste gas carbon dioxide. Smoke damages the lungs so much that the alveoli become less
stretchy. This means it's harder for the lungs to take in the oxygen we need and harder to get rid of carbon
dioxide. When the alveoli are damaged like this, smokers can feel short of breath and tired. Their heart
has to pump much harder to give their body the oxygen it needs. Over time, this damage can lead to
COPD and heart disease.
Signs of lung damage from smoking
It's common for smokers to ignore or downplay the symptoms of lung damage:
o feeling out of breath when walking up a short flight of stairs
o coughing
o spitting up mucous
o repeat chest infections
These are not signs of aging or simply being out of shape. These are real signs of the damage that
smoking is doing to your lungs. If you have these signs of smoking damage to your lungs, see you doctor.
Unless you do something now, these symptoms will keep getting worse.
How smoking hurts the rest of our body
Smoking doesn't just damage our lungs. There are over 4,000 dangerous chemicals in cigarettes, cigars
and pipes smoke for example: carbon monoxide (found in car exhaust), arsenic (rat poison) , ammonia
(found in window cleaner), acetone (found in nail polish remover) , hydrogen cyanide (gas chamber
poison), napthalene (found in mothballs), sulphur Compounds (found in matches), lead, volatile Alcohol ,
formaldehyde (used as embalming fluid), butane (lighter fluid). Many of these chemicals are cancercausing (carcinogen).It puts you at high risk for dozens of other serious disease, including cancer. Read
more about the health effects of smoking.
Modified from Canadian Lung Association.http://www.lung.ca/protect-protegez/tobacco-tabagisme/factsfaits/index_e.php
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II. Pulmonary Test
Pulmonary test is used to evaluate the symptoms and sign of lung diseases and to screen the risk of
pulmonary diseases. Spirometry is the measurement of the air movement and lung capacity. To provide
an accurate diagnosis, pulmonary test is usually companied with other tests. In this exercise, we just want
to learn the different aspects of a pulmonary test and its relationship with cardiovascular system. Figure 1
shows the components of the respiratory cycle. Three of these components are important. They are the
forced vital capacity (FVC), the forced expiratory volume in one second (FEV1) and the FEV1/FVC ratio.
Typically, an FEV1 / FVC ratio below 0.70 indicates that a patient is suffering from obstructive lung
disease. Table 1 compares the obstructive and restrictive pulmonary diseases. Obstructive pulmonary
disease refers to a group of diseases that are caused airflow blockage and narrowing of airways. It
includes emphysema, chronic bronchitis, and in some cases asthma. Restrictive lung diseases decrease
the total volume of air the lungs can hold, due to a decrease in the elasticity of the lungs or the chest wall
to expand during inhalation. Examples of restrictive lung diseases are sarcoidosis and pulmonary fibrosis.
Figure 1 Lung capacity ( diagram from www. Hakeem-sy.com)
Part III Case study of a smoker
Joe Smith is a 69-year-old male with a 50-year history of smoking 2 packs of cigarettes a day (i.e. 100pack-year smoking history). Over the past 5 years, he has become increasingly short of breath. At first, he
noticed this only when exercising, but now he is even short of breath at rest. Over the past two years, he
has had several bouts of lower respiratory tract infection treated successfully with antibiotics. His
shortness of breath hasn't subsided, and his breathing is assisted by use of his accessory muscles of
respiration. The microscopic changes of his lung are typical for smokers like him.
Normal lung
His
the
2
pulmonary function testing
graph below:
revealed
The lung of Joe Smith
Figure 2 Joe’s Pulmonary Function Test
Questions:
1) Based on the figures 1 and 2 above and page 472 figure 16.16 of your text book, fill in the following
data for Joe:
i)
tidal volume (TV) ____________
ii) inspiratory reserve volume (IRV) ______________
iii) expiratory reserve volume (ERV) _______________
iv) forced vital capacity (FVC) ______________
v) forced expiratory volume in one second FEV1 ___________________
vi) FEV1 / FVC ratio ___________
b) What pattern of lung disease may result in this FEV1/FVC ratio? _________________
2) Based on the information given on Joe above and your knowledge about the smokers in general,
describe the changes at microscopic level occurring in Joe's lungs.
3) Compare the given histology slides of normal lung on page 2, emphysema lung (from lecture) and
Joe’s lung, does he seems to have emphysema?
4) What effect do these microscopic changes have on Joe's ability to transfer oxygen and carbon dioxide
in the lungs?
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5) Define hematocrit.
6) Blood testing showed that Joe's hematocrit to be 59% (normal = 42-54%). Why was his hematocrit so
high? Explain the physiological mechanisms that contribute to his high hematocrit (include sensor,
signal molecule and the organ that release it).
7) Joe’s arterial blood tests revealed the following:
pO2 = 73 mm Hg (normal= 80-105 mm Hg)
pCO2 = 50 mm Hg (normal 35- 45 mm Hg)
pH = 7.32 (normal = 7.35-7.45)
Hb-O2 sat (hemoglobin-oxygen saturation) = 84% (normal = 95-98%)
i.
Why was Joe's pCO2 increased above normal?
ii.
Define pH.
iii.
Why was his arterial blood pH below normal? (Hint: include chemical reaction formula)
iv.
How is the breathing monitored and regulated in a normal human?
v.
Joe's pO2 is clearly below the normal range. One's first instinct might be to give him air to
breathe that is 100% oxygen. Why would this be dangerous for him (hardest question, give it
a try anyway)?
8) Why is Joe susceptible to lower respiratory tract infections?
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