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Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition.

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Presentation on theme: "Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition."— Presentation transcript:

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

2 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Anatomy of Ventilation Pulmonary ventilation –Process of air moving in and out of lungs Anatomy –Trachea –Bronchi –Bronchioles –Alveoli

3 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

4 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition The Lungs Provide a large surface area (50 − 100 m 2 ) Highly vascularized to allow for gas exchange

5 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition The Alveoli The lungs contain 600 million membranous sacs called alveoli. Characteristics of alveoli –Elastic –Thin walled Very small blood–gas barrier

6 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

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

8 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Mechanics of Ventilation Conducting zone (anatomic dead space) –Trachea –Bronchioles Respiratory zone –Respiratory bronchioles –Alveolar ducts –Alveoli

9 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

10 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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.

11 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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

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

13 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Surfactant Resistance to expansion of the lungs increases during inspiration due to surface tension on alveoli. Surfactant _ a lipoprotein mix of phospholipids, proteins, and Ca 2+ produced by alveolar epithelial cells _ mixes with fluid around alveoli. Surfactant disrupts and lowers surface tension.

14 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Lung Volumes & Capacities Are measured using a spirometer Lung volumes vary with –Age –Size (mainly stature) –Gender

15 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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

16 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Residual Lung Volume RLV averages 0.8 − 1.4 L RLV increases with age as lung elasticity decreases.

17 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Total Lung Capacity RLV + FVC = TLC

18 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

19 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Dynamic Lung Volumes Dynamic ventilation depends upon –Maximal FVC of lungs –Velocity of flow Velocity of flow is influenced by lung compliance.

20 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition FEV-to-FVC Ratio FEV 1 /FVC indicates pulmonary airflow capacity. Healthy people average ~ 85% of FVC in 1 second. Obstructive diseases result in significant lower FEV 1 /FVC.

21 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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.

22 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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 O 2 exchange.

23 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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.

24 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Pulmonary Ventilation Volume of air moved into or out of total respiratory tract each minute Air volume that ventilates only alveolar chambers each minute

25 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Minute Ventilation Minute ventilation –Volume of air breathed each minute V E Minute ventilation increases dramatically during exercise. –Values up to 200 L · min -1 have been reported. –Average person ~ 100 L · min -1 Despite huge V E, TVs rarely exceed 60% VC.

26 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Alveolar Ventilation Anatomic dead space –Averages 150 − 200 mL Only ~ 350 mL of the 500 mL TV enters alveoli.

27 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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.

28 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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.

29 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Physiologic Dead Space Occurs when there is either 1. Inadequate ventilation 2. Inadequate blood flow

30 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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

31 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

32 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Hyperventilation An increase in pulmonary ventilation that exceeds O 2 needs of metabolism Hyperventilation decreases P CO 2.

33 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Dyspnea Subjective distress in breathing During exercise, respiratory muscles may fatigue, resulting in shallow, ineffective breathing and increased dyspnea.

34 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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

35 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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

36 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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

37 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Postexercise Coughing Related to water loss and the drying of the throat


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