Download Biology 13A Lab #12: The Respiratory System

Bio13A Lab Manual
Biology 13A Lab #12: The Respiratory System
Lab #12 Table of Contents:
 Expected Learning Outcomes .
.
 Introduction
.
.
.
.
 Activity 1: Structures of the Respiratory
 Activity 2: Measuring Respiration .
 Activity 3: Film: “Deadly Ascent” .
Expected Learning
Outcomes
At the end of this lab, you
will be able to
 locate the major gross
structures of the
respiratory system on
the human torso
model;
 use a computer and
physiological data
collection device
(Vernier) to monitor the
respiratory rate of an
individual;
 determine the effect of
increased carbon
dioxide on breathing
rate and depth; and
 explore the
physiological effects of
high altitude.
.
.
.
.
System
.
.
.
.
94
95
96
96
100
Figure 12.1: Lungs
94
Bio13A Lab Manual
Introduction
The organs of the respiratory
system include the nose, nasal
cavity, sinuses, pharynx, larynx,
trachea, respiratory tree, and
lungs. They function to
transport air to the air sacs of
the lungs (the alveoli) where gas
exchange occurs. The process of
transporting and exchanging
gases between the atmosphere
and the body cells is respiration.
The process of taking in air is
known as inspiration, while the
process of blowing out air is
called expiration. A respiratory
cycle consists of one inspiration
and one expiration.
The point of respiration is to
allow you to obtain oxygen,
eliminate carbon dioxide, and
regulate the blood’s pH level.
Respiration rate (breaths per
minute) and depth (volume of air
inhaled and exhaled with each
breath) varies due to changes in
blood chemistry that are
monitored by the brain. For
example, when you exercise,
demand for oxygen increases
because the cells require more
ATP. In turn, more carbon
dioxide is produced by cells and
diffuses to the blood. The rise in
carbon dioxide leads to a
decrease in pH, causing the
blood to be more acidic. The
brain is especially sensitive to pH
levels; as pH levels in the blood
fall, the brain stimulates more
rapid breathing and deeper
breathing. The effect is to draw
more air into the lungs, to
transport more oxygen to the
cells, and lower pH and CO2
levels.
Check Your Understanding: Answer the following questions based on
your reading of the introduction.
1. Where does gas exchange occur?
2. What is one complete respiratory cycle? Define breathing rate and
breathing depth.
3. What happens to breathing rate and depth during exercise? What are
the changes in blood chemistry that lead to the observed changes
during exercise.
95
Bio13A Lab Manual
Activity 1: Structures of the Respiratory System
Locate the following structures on the model of the human torso and the
real skull.






















Nostrils (external nares)
Nasal cavity
Nasal septum
Nasal conchae
 Superior Nasal concha
 Middle Nasal Concha
 Inferior Nasal Concha
Palatine Tonsils
Pharyngeal Tonsils (Adenoids)
Sinuses
Frontal Sinus
Maxillary Sinus
Pharynx
Larynx
Vocal Cords
Thyroid Cartilage (Adam’s Apple)
Cricoid Cartilage
Epiglottis
Glottis
Trachea
Bronchi
Lung
Lobes
Visceral Pleura
Parietal Pleura
1. Breathing can also be called __________________.
2. When the diaphragm contracts, the size of the thoracic cavity
__________________.
Activity 2: Measuring Respiration
The rate at which your body performs a respiratory cycle is dependent
upon levels of oxygen and carbon dioxide in your blood.
You will monitor the respiratory patterns of one member of your group under
different conditions. A respiration belt will be strapped around the test subject and
connected to a computer-interfaced gas pressure sensor. Each respiratory cycle will be
recorded by the computer, allowing you to calculate a respiratory rate for comparison at
96
Bio13A Lab Manual
different conditions.
PROCEDURE
1. Prepare the computer for data collection by opening the Experiment 26 folder
from the Biology with Computers folder of Logger Pro. Then open the experiment
file that matches the probe you are using. There are two graphs displayed and two
Meter windows. The top graph’s vertical axis has pressure scaled from 96 to 110
kPa. The horizontal axis has time scaled from 0 to 180 seconds. The data rate is
set to take five samples per second. The Meter window to the right displays live
pressure readings from the sensor. The lower graph’s vertical axis has respiration
rate scaled from 0 to 20 breaths/minute. The horizontal
axis has time scaled from 0 to 180 seconds. The Meter
window to the right displays the calculated respiration rate
when data are being collected. (Note: kPa is the symbol
for kilopascals (1000 Pa = 1 kPa). A pascal is a
measurement of force per unit area.)
Figure 12.2
2. If your Gas Pressure Sensor has a blue plastic valve on it, place the valve in the
position shown in Figure 12.2.
3. Select one member of the group as the test subject. Wrap the Respiration Monitor
Belt snugly around the test subject’s chest. Press the Velcro strips together at the
back. Position the belt on the test subject so that the belt’s air bladder is resting over
the base of the rib cage and in alignment with the elbows as shown in Figure 12.3.
Figure 12.3
4. Attach the Respiration Monitor Belt to the Gas Pressure Sensor. There are two rubber
tubes connected to the bladder. One tube has a white Luer-lock connector at the end
and the other tube has a bulb pump attached. Connect the Luer-lock connector to the
stem on the Gas Pressure Sensor with a gentle half turn.
4. Have the test subject sit upright in a chair. Close the shut-off screw of the bulb pump
by turning it clockwise as far as it will go. Pump air into the bladder by squeezing on
the bulb pump. Fill the bladder as full as possible without being uncomfortable.
97
Connect tubing
here
Bio13A Lab Manual
5. The pressure reading displayed in the Meter window should increase about 6 kPa
above the initial pressure reading (e.g., at sea level, the pressure would increase from
about 100 to 106 kPa). At this pressure, the belt and bladder should press firmly
against the test subject’s diaphragm. Pressures will vary, depending upon how tightly
the belt was initially wrapped around the test subject.
7. As the test subject breathes in and out normally, the displayed pressure alternately
increases and decreases over a range of about 2 – 3 kPa. If the range is less than 1
kPa, it may be necessary to pump more air into the bladder. Note: If you still do not
have an adequate range, you may need to tighten the belt.
Part l Holding of Breath
8. Instruct the test subject to breathe normally. Start collecting data by clicking Collect .
When data has been collected for 60 seconds, have the test subject hold his or her
breath for 30 to 45 seconds. The test subject should breathe normally for the
remainder of the data collection once breath has been released.
9. Examine the respiration rates recorded in the bottom graph by clicking the Examine
button, . As you move the mouse pointer from point to point on the graph the data
values are displayed in the examine window. Determine the respiration rate before
and after the test subject’s breath was held and record the values in Table 12.1.
Part ll Rebreathing of Air
10. Prepare the computer for data collection by opening the Experiment 26B folder from
the Biology with Computers folder of Logger Pro. Then open the experiment file that
matches the probe you are using. The vertical axis has pressure scaled from 98 to 112
kPa. The horizontal axis has time scaled from 0 to 300 seconds. The data rate is set to
take five samples per second. The Meter window to the right displays live pressure
readings from the sensor.
11. Place a small paper bag into a plastic produce bag. Have the test subject cover his or
her mouth with the bags, tight enough to create an air-tight seal. The test subject
should breathe normally into the bags throughout the course of the data collection
process.
12. Click Collect to begin data collection. Again, the test subject should be sitting and
facing away from the computer screen. Collect respiration data for the full 300
seconds while breathing into the sack. Important: Anyone prone to dizziness or
nausea should not be tested in this section of the experiment. If the test subject
experiences dizziness, nausea, or a headache during data collection, testing should be
stopped immediately.
13. Once you have finished collecting data in Step 12, calculate the maximum height of
the respiration waveforms for the intervals of 0 to 30 seconds, 120 to 150 seconds,
and 240 to 270 seconds:
a. Move the mouse pointer to the beginning of the section you are examining. Hold
down the mouse button. Drag the pointer to the end of the section and release the
mouse button.
b. Click the Statistics button, , to determine the statistics for the selected data.
c. Subtract the minimum pressure value from the maximum value (in kPa).
98
Bio13A Lab Manual
d. Record this value for each section as the wave amplitude in Table 2.
DATA
Table 12.1
Holding of Breath
Before holding breath
After holding breath
_______ breaths / minute
_______ breaths / minute
Table 2
Rebreathing of Air: Amplitudes of Respiration Waves
0 to 30 seconds
120 to 150 seconds
240 to 270 seconds
________ kPa
________ kPa
________ kPa
QUESTIONS
1. Did the respiratory rate of the test subject change after holding his or her breath? If
so, describe how it changed.
2. What is different about the size (amplitude) or shape (frequency) of the respiratory
waveforms following the release of the test subject’s breath? Explain.
3. What would be the significance of an increase in the amplitude and frequency of the
waveform while the test subject was breathing into the bag?
99
Bio13A Lab Manual
4. How did the respiratory waveforms change while the test subject was breathing into
the bag? How would you interpret this result?
5. Explain how you think an increase in carbon dioxide in the blood affects your
breathing. What is the mechanism?
This lab is a modified version of a lab from University of Pittsburgh’s Science in Motion program for
science education. <www.upb.pitt.edu/interior3Default.aspx?menu_id=42&id=7499>
Activity 3: Film: Deadly Ascent
High altitude poses physiological challenges. As one ascends higher, the
air pressure lessens, and the amount of oxygen decreases. Humans are
not adapted to conditions of low levels of oxygen, or extreme cold. In this
film, a team is followed on their climb of Denali (also known as Mt.
McKinley), and the effects of altitude and cold temperatures is observed.
Background: Climbers who ascend Denali (Mt. McKinley) can experience
health problems in response to extreme conditions—high altitude, low
atmospheric pressure, and severe cold. The mountain is 6,194 meters
from its base to its summit. Most humans are adapted to living on
Earth's surface where air pressure is about 14.7 pounds per square inch.
At high elevations, because there is less oxygen in a given amount of air,
humans who are not acclimated to the environment experience hypoxia,
or oxygen deprivation, and they experience health complications such as
hypothermia, frostbite, and sometimes gangrene due to intense wind and
cold. This chart shows some air pressures at different elevations:
Altitude
(in feet)
Barometric Pressure (mm Hg)
Barometric Pressure*
(in
Atmospheres)
0 (Sea Level)
760
1
3000 feet
684
0.9
10,000
532
0.7
18,000 (5,600m)
380
0.5
23,000 (7,200 m)
304
0.4
30,000 (9,400 m)
228
0.3
From Darwish, A. 2003. Aerospace Medicine: Part 1. The Internet Journal of Pulmonary
Medicine. Volume 3 Number 2. <www.ispub.com/xml/journals/ijpm/vol3n2
100
Bio13A Lab Manual
Take notes and be able to answer the following questions:
1. What conditions on Denali pose physiological challenges for climbers?
2. What is hypoxia?
3. Define and describe symptoms for

hypothermia

hyperthermia

Acute Mountain Sickness (AMS)

High Altitude Pulmonary Edema (HAPE).
4. What is oxygen saturation? How are oxygen saturation levels are
affected during a mountain climb? What problems can occur when
the levels get too low?
101