BIOL 207: Lab 10
BIOLOGY 207 LABORATORY 10 LUNG FUNCTION
GENERAL STATEMENT REGARDING SUBJECT MATTER
During this laboratory, we are going to measure some important lung volumes and capacities. In addition, we will
investigate the control of the rate of breathing. The instrument used to measure lung volumes and capacities is called a
spirometer. We will also use the PowerLab setup to investigate your lung function.
Normally, your lungs contain about 2 to 2.5 liters of air but this volume is changing as you breathe. In healthy young
males, the maximum air that the lungs can hold is usually around 5.5 liters. In healthy young women, the maximum is
normally about 4.0 liters. This total lung capacity varies between people based on build, age, how easily the lungs will
stretch (distensibility) and whether disease is present. Normally, you breathe in and out without giving it much
thought. Like the tides coming in and going out with regularity, the change in volume in your lungs while breathing is
your tidal volume. Tidal volume is normally about 500 ml. If you were attached to a spirometer, you would be
breathing into a tube that was connected to a floating bell, which controlled a pen, which was writing on paper slowly
turning on a drum. Thus, the pen would register the tidal flow of air into and out of your lungs by tracing a line on the
paper. If the paper is calibrated to the floating bell, you can get a measurement of the movement of air or the change
in lung volume with time. This tracing on the paper would be showing you your tidal volume. The tracing is called a
spirogram. You know that getting a little exercise can make you breathe faster and also make you breath deeper. These
changes can also be registered on the spirogram. We will discuss the names of the volumes and capacities you will be
measuring below.
How rapidly and easily air goes into and comes out of your lungs depends upon several factors. The pressure
difference between the air inside your lungs and outside in the atmosphere is very important as it is the driving force
for air movement. You generate this pressure difference by changing lung volume. If you increase lung volume, the
pressure of the gas inside the lung goes down. If you decrease lung volume, the pressure of the air in the lung
increases. Another factor important in air movement is the resistance to air flow. The radius of the conducting airways
is the primary determinant of resistance to air flow. As the ‘tubing’ increases in diameter (radius), the resistance goes
down rapidly. There are conditions called chronic obstructive pulmonary diseases (asthma, chronic bronchitis,
emphysema) characterized by increased resistance to air flow. There are also non-chronic conditions such as a stuffy
nose, a condition characterized by swollen nasal passages and mucus accumulation. When we have a stuffy nose, we
have more difficulty breathing due to the increased airway resistance of the narrowed nasal passages. You will also
conduct an experiment to check your group’s volunteer for obstructive lung disease.
The rhythmic pattern of breathing is controlled by rhythmic neural activity. This neural activity is generated by
respiratory centers in the brain stem. There must also be additional control because as our physiology changes (due to
exercise etc.), our breathing rate, or breaths per minute, also changes. The primary regulator of ventilation is the
carbon dioxide-generated hydrogen ion concentration in the brain extracellular fluid. An increase in plasma carbon
dioxide results in an increase in brain carbon dioxide that generates an increase in hydrogen ion concentration (lower
pH) that strongly stimulates the central chemoreceptors in the brain. These chemoreceptors drive the respiratory
centers. You increase your ventilation when carbon dioxide builds up in your plasma and if carbon dioxide is reduced,
your ventilation is reduced. You will be conducting experiments to demonstrate the changes in carbon dioxide
concentration in the air you exhale as a result of exercise, and exercises to demonstrate how a reduction in carbon
dioxide in your plasma (as occurs during hyperventilation) changes your breathing rate.
READING in HUMAN PHYSIOLOGY, 14th Edition, Stuart Ira Fox
thoracic cavity: pp. 533-536 physical ventilation: pp. 536-538 inspiration
and expiration: pp. 540-542 testing lung function: pp. 542-543 lung
volumes, lung capacities: pp. 542-544 lung disorders: pp. 544-546
10.1
, BIOL 207: Lab 10
NOTICE THERE IS A LOT OF READING ASSOCIATED WITH THIS LAB SO IT LOOKS LONG.
HOWEVER, WITH ORGANIZATION, THE EXERCISES CAN EASILY BE DONE WITHIN THE
TIME AVAILABLE TO YOU. PLEASE READ AND PLAN AHEAD!
OBJECTIVES
1. Explain breathing mechanics.
2. Define the lung volumes and capacities and explain the significance of these measurements.
3. Perform spirometry to establish simple tidal volume, vital capacity, total lung capacity, inspiratory
capacity, inspiratory reserve volume, and expiratory reserve volume.
4. Use forced expiratory volume (FEV) measurements to investigate lung disorders.
5. Explain restrictive and obstructive lung disorders.
6. Explain the importance of carbon dioxide in regulating ventilation.
7. Explain the relationship between the amount of carbon dioxide in solution, and pH of solutions.
8. Demonstrate the accumulation of carbon dioxide in blood and in exhaled gas after exercise.
9. Demonstrate the importance of buffers in maintaining proper plasma pH.
SPIROMETRY;
We have already discussed tidal volume. The following is a list of lung volumes and capacities that you
may be testing and calculating during the following exercises. The numbers below are examples for young
men; women would be about 20% less.
Tidal Volume (TV). This is normally about 500 ml. It is the volume of air entering your lungs or leaving
your lungs in a single breath.
Inspiratory Reserve Volume (IRV). After a normal inhale, you are able to breath in more air if you try.
This extra amount of air over and above the resting tidal volume is called the inspiratory reserve
volume. Generally, this is about 3000 ml.
Expiratory Reserve Volume (ERV). After a normal expiration, you can actively contract your expiratory
muscles and exhale an extra volume of air. This is the amount of air you can breathe out after a
normal exhale. This is generally about 1000 ml.
Residual Volume (RV). Even after the maximal expiration, there is a minimum volume of air that remains
in your lungs. You can’t really measure this directly because this volume of air doesn’t go anywhere.
This volume is determined indirectly and it is about 1200 ml, on average.
Total Lung Capacity (TLC). This is the maximum amount of air the lungs can actually hold. It is the
amount of air in the lungs after a maximum inhalation. The TLC is the vital capacity (VC) plus the
residual volume (RV), or TLC = VC + RV.
Vital Capacity (VC). After a maximal inhalation, you forcibly exhale air from your lungs. The maximum
amount of air that you can move out in a single breath after a maximal inhalation is the vital
capacity. This can also be defined as the maximum volume change possible within the lungs under
physiological conditions. VC = IRV + TV + ERV. This is about 4500 ml for men.
Functional Residual Capacity (FRC). This is the volume of air in the lungs after a normal, relaxed
exhalation. FRC = ERV + RV. On average, this is 2200 ml.
Inspiratory Capacity (IC). This is the maximum amount of air that you can breathe in after a normal
expiration. Breathe out like normal, then take in as much air as possible. IC = IRV + TV.
Forced Expiratory Volume in one second (FEV1). This is the volume of air you can expire during the first
second of expiration in a vital capacity test. Normally, about 80% of the air can be forcibly expired
in one second from lungs that are at maximal inflation. Breathe in as much as possible, then exhale
as rapidly as possible. What % of the total came out during the first second? This measurement
indicates the maximal air flow possible and can be used to look for obstructive disorders.
Take a look in your textbook on page 543, figure 16.15, and you will see graphically these volumes and
BIOLOGY 207 LABORATORY 10 LUNG FUNCTION
GENERAL STATEMENT REGARDING SUBJECT MATTER
During this laboratory, we are going to measure some important lung volumes and capacities. In addition, we will
investigate the control of the rate of breathing. The instrument used to measure lung volumes and capacities is called a
spirometer. We will also use the PowerLab setup to investigate your lung function.
Normally, your lungs contain about 2 to 2.5 liters of air but this volume is changing as you breathe. In healthy young
males, the maximum air that the lungs can hold is usually around 5.5 liters. In healthy young women, the maximum is
normally about 4.0 liters. This total lung capacity varies between people based on build, age, how easily the lungs will
stretch (distensibility) and whether disease is present. Normally, you breathe in and out without giving it much
thought. Like the tides coming in and going out with regularity, the change in volume in your lungs while breathing is
your tidal volume. Tidal volume is normally about 500 ml. If you were attached to a spirometer, you would be
breathing into a tube that was connected to a floating bell, which controlled a pen, which was writing on paper slowly
turning on a drum. Thus, the pen would register the tidal flow of air into and out of your lungs by tracing a line on the
paper. If the paper is calibrated to the floating bell, you can get a measurement of the movement of air or the change
in lung volume with time. This tracing on the paper would be showing you your tidal volume. The tracing is called a
spirogram. You know that getting a little exercise can make you breathe faster and also make you breath deeper. These
changes can also be registered on the spirogram. We will discuss the names of the volumes and capacities you will be
measuring below.
How rapidly and easily air goes into and comes out of your lungs depends upon several factors. The pressure
difference between the air inside your lungs and outside in the atmosphere is very important as it is the driving force
for air movement. You generate this pressure difference by changing lung volume. If you increase lung volume, the
pressure of the gas inside the lung goes down. If you decrease lung volume, the pressure of the air in the lung
increases. Another factor important in air movement is the resistance to air flow. The radius of the conducting airways
is the primary determinant of resistance to air flow. As the ‘tubing’ increases in diameter (radius), the resistance goes
down rapidly. There are conditions called chronic obstructive pulmonary diseases (asthma, chronic bronchitis,
emphysema) characterized by increased resistance to air flow. There are also non-chronic conditions such as a stuffy
nose, a condition characterized by swollen nasal passages and mucus accumulation. When we have a stuffy nose, we
have more difficulty breathing due to the increased airway resistance of the narrowed nasal passages. You will also
conduct an experiment to check your group’s volunteer for obstructive lung disease.
The rhythmic pattern of breathing is controlled by rhythmic neural activity. This neural activity is generated by
respiratory centers in the brain stem. There must also be additional control because as our physiology changes (due to
exercise etc.), our breathing rate, or breaths per minute, also changes. The primary regulator of ventilation is the
carbon dioxide-generated hydrogen ion concentration in the brain extracellular fluid. An increase in plasma carbon
dioxide results in an increase in brain carbon dioxide that generates an increase in hydrogen ion concentration (lower
pH) that strongly stimulates the central chemoreceptors in the brain. These chemoreceptors drive the respiratory
centers. You increase your ventilation when carbon dioxide builds up in your plasma and if carbon dioxide is reduced,
your ventilation is reduced. You will be conducting experiments to demonstrate the changes in carbon dioxide
concentration in the air you exhale as a result of exercise, and exercises to demonstrate how a reduction in carbon
dioxide in your plasma (as occurs during hyperventilation) changes your breathing rate.
READING in HUMAN PHYSIOLOGY, 14th Edition, Stuart Ira Fox
thoracic cavity: pp. 533-536 physical ventilation: pp. 536-538 inspiration
and expiration: pp. 540-542 testing lung function: pp. 542-543 lung
volumes, lung capacities: pp. 542-544 lung disorders: pp. 544-546
10.1
, BIOL 207: Lab 10
NOTICE THERE IS A LOT OF READING ASSOCIATED WITH THIS LAB SO IT LOOKS LONG.
HOWEVER, WITH ORGANIZATION, THE EXERCISES CAN EASILY BE DONE WITHIN THE
TIME AVAILABLE TO YOU. PLEASE READ AND PLAN AHEAD!
OBJECTIVES
1. Explain breathing mechanics.
2. Define the lung volumes and capacities and explain the significance of these measurements.
3. Perform spirometry to establish simple tidal volume, vital capacity, total lung capacity, inspiratory
capacity, inspiratory reserve volume, and expiratory reserve volume.
4. Use forced expiratory volume (FEV) measurements to investigate lung disorders.
5. Explain restrictive and obstructive lung disorders.
6. Explain the importance of carbon dioxide in regulating ventilation.
7. Explain the relationship between the amount of carbon dioxide in solution, and pH of solutions.
8. Demonstrate the accumulation of carbon dioxide in blood and in exhaled gas after exercise.
9. Demonstrate the importance of buffers in maintaining proper plasma pH.
SPIROMETRY;
We have already discussed tidal volume. The following is a list of lung volumes and capacities that you
may be testing and calculating during the following exercises. The numbers below are examples for young
men; women would be about 20% less.
Tidal Volume (TV). This is normally about 500 ml. It is the volume of air entering your lungs or leaving
your lungs in a single breath.
Inspiratory Reserve Volume (IRV). After a normal inhale, you are able to breath in more air if you try.
This extra amount of air over and above the resting tidal volume is called the inspiratory reserve
volume. Generally, this is about 3000 ml.
Expiratory Reserve Volume (ERV). After a normal expiration, you can actively contract your expiratory
muscles and exhale an extra volume of air. This is the amount of air you can breathe out after a
normal exhale. This is generally about 1000 ml.
Residual Volume (RV). Even after the maximal expiration, there is a minimum volume of air that remains
in your lungs. You can’t really measure this directly because this volume of air doesn’t go anywhere.
This volume is determined indirectly and it is about 1200 ml, on average.
Total Lung Capacity (TLC). This is the maximum amount of air the lungs can actually hold. It is the
amount of air in the lungs after a maximum inhalation. The TLC is the vital capacity (VC) plus the
residual volume (RV), or TLC = VC + RV.
Vital Capacity (VC). After a maximal inhalation, you forcibly exhale air from your lungs. The maximum
amount of air that you can move out in a single breath after a maximal inhalation is the vital
capacity. This can also be defined as the maximum volume change possible within the lungs under
physiological conditions. VC = IRV + TV + ERV. This is about 4500 ml for men.
Functional Residual Capacity (FRC). This is the volume of air in the lungs after a normal, relaxed
exhalation. FRC = ERV + RV. On average, this is 2200 ml.
Inspiratory Capacity (IC). This is the maximum amount of air that you can breathe in after a normal
expiration. Breathe out like normal, then take in as much air as possible. IC = IRV + TV.
Forced Expiratory Volume in one second (FEV1). This is the volume of air you can expire during the first
second of expiration in a vital capacity test. Normally, about 80% of the air can be forcibly expired
in one second from lungs that are at maximal inflation. Breathe in as much as possible, then exhale
as rapidly as possible. What % of the total came out during the first second? This measurement
indicates the maximal air flow possible and can be used to look for obstructive disorders.
Take a look in your textbook on page 543, figure 16.15, and you will see graphically these volumes and
