PHYSIOEX 37B
Dr. Kim Wilson
OBJECTIVES
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To define the following terms: ventilation, inspiration,
expiration, forced expiration, tidal volume, expiratory
reserve volume, inspiratory reserve volume, residual
volume, vital capacity, forced expiratory volume,
minute respiratory volume, surfactant, and
pneumothorax.
To describe the role of muscles and volume changes in
the mechanics of breathing.
To understand that the lungs do not contain muscle
and that respirations are therefore caused by external
forces.
To explore the effect of changing airway resistance on
breathing.
To understand the effects of hyperventilation,
rebreathing, and breath holding on the CO2 level in
the blood.
RESPIRATORY SYSTEM: MECHANICS
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Two phases of pulmonary ventilation
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Inspiration
Air is taken into the lungs
 External intercostal muscles and the diaphragm contract
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Expiration
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Air is expelled from the lungs
Inspiratory muscles relax,causing the diaphragm
to rise and the chest wall to move inward
 Forced expiration – Ex. blowing up a balloon
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SIMULATING SPIROMETER: MEASURING
RESPIRATORY VOLUMES AND CAPACITIES
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Normal quiet breathing moves about 500 ml (0.5 liter) of air
(the tidal volume) in and out of the lungs with each breath
(varies)
Normal Respiratory Volumes
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Tidal volume (TV): Amount of air inhaled or exhaled with each
breath under resting conditions (500 ml)
Expiratory reserve volume (ERV): Amount of air that can be
forcefully exhaled after a normal tidal volume exhalation (1200 ml)
Inspiratory reserve volume (IRV): Amount of air that can be
forcefully inhaled after a normal tidal volume inhalation (3100 ml)
Residual volume (RV): Amount of air remaining in the lungs after
complete exhalation (1200 ml)
Vital capacity (VC): Maximum amount of air that can be exhaled
after a normal maximal inspiration (4800 ml)
VC = TV + IRV +ERV
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Total lung capacity (TLC): Sum of vital capacity and
residual volume
PULMONARY FUNCTION TESTS
Forced vital capacity (FVC): Amount of air
that can be expelled when the subject takes the
deepest possible breath and exhales as
completely and rapidly as possible
 Forced expiratory volume (FEV1): Measures
the percentage of the vital capacity that is
exhaled during 1 second of the FVC test
(normally 75% to 85% of the vital capacity
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INSTRUCTIONS
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Go to Exercise 37B PEx-109 in the back of the
Marieb lab manual.
Read Pex 109-110 to Activity 1.
Insert the PhysioEx CD and select Main Menu, then
#7: Respiratory System Mechanics, then Respiratory
Volumes from the Experiment drop down menu.
Complete Activity 1: Measuring Respiratory
Volumes, Steps 1-5 on PEx-110. Answer
Question #1 from Activity 1 in the Questions section.
For these experiments you can equate radius with
diameter.
Complete Step 8 from Activity 1 on PEx-112.
Answer the remaining questions from Activity 1 in
the Questions section.
ACTIVITY 1 – MEASURING RESPIRATORY
VOLUMES
SIMULATING VARIATIONS IN BREATHING
INSTRUCTIONS CONT.
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11.
Complete Activity 2: Examining the Effect of
Changing Airway Resistance on Respiratory Volumes,
Steps 1-7 on Pex-112. DO NOT Record the FEV1 or Vital
Capacity values in the chart in your lab manual, instead
record them in the chart (Question #1) in the Questions
section for Activity 2. Also, calculate the FEV1 (%) by
dividing the FEV1 volume by the Vital Capacity volume and
multiplying by 100. Record the FEV1 (%) in the chart
(Question #1) in the Questions section for Activity 2.
Answer the remaining questions for Activity 2 in the
Questions Section.
Read Simulating Variations in Breathing on PEx-115.
Select Variations in Breathing from the Experiment drop
down menu.
Complete Activity 5 (Pex-118): Exploring Various
Breathing Patterns, Steps 1-7; Rebreathing, Steps 1
and 2 and Breath Holding, Steps 1-4. Do not answer the
questions in your lab manual from this section; instead,
answer the questions for Activity 5 in the Questions section.