1. Pulmonary Structure and Function
Chapter 12
Pulmonary Structure and Function
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

2. Anatomy of Ventilation
Pulmonary ventilation
Process of air moving in and out of lungs
Anatomy
Trachea
Bronchi
Bronchioles
Alveoli
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

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4. The Lungs Provide a large surface area (50 − 100 m2)
Highly vascularized to allow for gas exchange
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

5. The Alveoli
The lungs contain 600 million membranous sacs called alveoli.
Characteristics of alveoli
Elastic
Thin walled
Very small blood–gas barrier
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

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7. The Alveoli Pores of Kohn allow for even dispersion of surfactant.
Surfactant decreases surface tension.
Pores also allow for gas interchange between alveoli.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

8. Mechanics of Ventilation
Conducting zone (anatomic dead space)
Trachea
Bronchioles
Respiratory zone
Respiratory bronchioles
Alveolar ducts
Alveoli
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

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10. Fick’s Law Explains gas exchange through the alveolar membranes
Gas diffuses through a tissue at a rate proportional to surface area and inversely proportional to its thickness.
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

11. Inspiration During inspiration Diaphragm contracts and flattens
Chest cavity elongates and enlarges and air expands in lungs
Intrapulmonic pressure decreases
Air is sucked in through nose and mouth
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

12. Expiration
During rest and light exercise, expiration is predominantly passive.
Stretched lung tissue recoils
Inspiratory muscles relax
Air moves to atmosphere
During strenuous exercise
Internal intercostals and abdominal muscles assist
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

13. Surfactant
Resistance to expansion of the lungs increases during inspiration due to surface tension on alveoli.
Surfactant _ a lipoprotein mix of phospholipids, proteins, and Ca2+ produced by alveolar epithelial cells _ mixes with fluid around alveoli.
Surfactant disrupts and lowers surface tension.
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

14. Lung Volumes & Capacities
Are measured using a spirometer
Lung volumes vary with
Age
Size (mainly stature)
Gender
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

15. Static Lung Volumes TV: Tidal volume: 0.4 − 1.0 L air/breath
IRV: Inspiratory reserve volume: 2.5 − 3.5 L
ERV: Expiratory reserve volume: 1.0 − 1.5 L
IRV and ERV decrease during exercise as TV increases
FVC: Forced vital capacity: 3 − 5 L
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

16. Residual Lung Volume RLV averages 0.8 − 1.4 L
RLV increases with age as lung elasticity decreases.
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

17. Total Lung Capacity RLV + FVC = TLC
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19. Dynamic Lung Volumes Dynamic ventilation depends upon
Maximal FVC of lungs
Velocity of flow
Velocity of flow is influenced by lung compliance.
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

20. FEV-to-FVC Ratio FEV1/FVC indicates pulmonary airflow capacity.
Healthy people average ~ 85% of FVC in 1 second.
Obstructive diseases result in significant lower FEV1/FVC.
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21. Maximum Voluntary Ventilation
MVV evaluates ventilatory capacity with rapid and deep breathing for 15 seconds.
MVV = 15 second volume × 4
MVV in healthy individuals averages 25% > ventilation than occurs during max exercise.
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

22. Exercise Implications
Gender Differences in Static and Dynamic Lung Functional Measures
Women have smaller lung function measures than men.
Highly fit women must work harder to maintain adequate alveolar-to-arterial O2 exchange.
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

23. Lung Function, Aerobic Fitness, and Exercise Performance
Little relationship exists among diverse lung volumes and capacities and exercise performance.
Maximum exercise is not limited by ventilation.
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

24. Pulmonary Ventilation
Volume of air moved into or out of total respiratory tract each minute
Air volume that ventilates only alveolar chambers each minute
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

25. Minute Ventilation Minute ventilation
Volume of air breathed each minute VE
Minute ventilation increases dramatically during exercise.
Values up to 200 L · min-1 have been reported.
Average person ~ 100 L · min-1
Despite huge VE, TVs rarely exceed 60% VC.
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26. Alveolar Ventilation Anatomic dead space
Averages 150 − 200 mL
Only ~ 350 mL of the 500 mL TV enters alveoli.
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

27. Dead Space vs. Tidal Volume
Anatomic dead space increases as TV increases.
Despite the increase in dead space, increases in TV result in more effective alveolar ventilation.
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

28. Ventilation−Perfusion Ratio
Ratio of alveolar ventilation to pulmonary blood flow
V/Q during light exercise ~ 0.8
V/Q during strenuous exercise may increase up to 5.0.
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

29. Physiologic Dead Space
Occurs when there is either
1. Inadequate ventilation
2. Inadequate blood flow
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

30. Rate vs. Depth
During exercise, both rate and depth of breathing increase.
Initially, larger increases in depth occur.
Followed by increases in rate and depth
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32. Hyperventilation
An increase in pulmonary ventilation that exceeds O2 needs of metabolism
Hyperventilation decreases PCO2.
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

33. Dyspnea Subjective distress in breathing
During exercise, respiratory muscles may fatigue, resulting in shallow, ineffective breathing and increased dyspnea.
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

34. Valsalva Maneuver
Closing the glottis following a full inspiration while maximally activating the expiratory muscles
Causes increase in intrathoracic pressure
Helps stabilize chest during lifting
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

35. Physiologic Consequences of Valsalva Maneuver
An acute drop in BP may result from a prolonged Valsalva maneuver.
Decreased venous return
Decreased flow to brain
Dizziness or fainting result
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

36. Respiratory Tract During Cold-Weather Exercise
Cold ambient air is warmed as it passes through the conducting zone.
Moisture is lost if the air is cold and dry.
Contributes to
Dehydration
Dry mouth
Irritation of respiratory passages
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37. Postexercise Coughing
Related to water loss and the drying of the throat
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McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition