1. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Chapter 23: Anatomy and Physiology of the Respiratory System

2. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Thoracic Contents

3. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Posterior Thoracic Cage

4. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Anterior Thoracic Cage

5. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Frontal Section of the Chest

6. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Inspiration and Expiration

7. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Structures of the Respiratory System

8. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Human Airways

9. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Cast of the Airways of the Lung

10. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomical Dead Space Conducting airways have no alveoli and no gas exchange occurs. Volume in this space is 150 mL.

11. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Role of Surfactant in the Lungs Surfactant is a complex of lipoproteins that line the alveoli and reduce surface tension across the air and liquid interface in the alveoli. It helps to keep alveoli open and participating in gas exchange. It helps to keep the alveoli dry to prevent pulmonary edema.

12. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Lobule of the Lung

13. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Circulation From Right Heart to Lungs and Left Heart

14. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomical Shunt in the Bronchial Circulation No gas exchange occurs in the bronchial circuit. The blood in the pulmonary vein is unoxygenated; this blood mixes with the oxygenated blood from the left side of the heart. Reason why the SaO2 is <100% on room air

15. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Partitioning of Respiratory Pressures

16. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Phases of Ventilation See Figure 23-12.

17. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Fick’s Law

18. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins How Disease Process Affects Alveolar- Capillary Gas Exchange Decrease in lung tissue means less surface area is available for gas exchange. Thicker alveolar-capillary membrane leads to decreased gas exchange. High altitudes or decrease in partial pressure of inspired air decreases gas exchange. The solubility and molecular weight of gases determine the ease of diffusion across the alveolar-capillary membrane.

19. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Normal Distribution of Ventilation Depends on Body Position Sit/stand: ventilate best in lower zones Supine: apex and base ventilate same; posterior lung > anterior lung Prone: anterior lung > posterior lung Lateral: dependent lung ventilates the best

20. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Explanation of Uneven Distribution of Blood Flow

21. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Ventilation-Perfusion Situations

22. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question In a client with pneumonia, which of the following ventilation-perfusion mismatches exists? A. Alveolar dead space B. Physiological shunt C. Silent unit D. Anatomical shunt

23. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer B. Physiological shunt Rationale: A physiological shunt (low ventilation-perfusion ratio) exists with pneumonia; the perfusion to the alveoli is adequate, but the gas exchange is not. An alveolar dead space (high ventilation-perfusion ratio) occurs in pulmonary embolus: the alveoli are getting adequate air exchange, but there is inadequate perfusion of blood to the alveoli. Silent unit can happen in a pneumothorax: both ventilation and perfusion are decreased. An anatomical shunt occurs with congenital heart disease.

24. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Oxyhemoglobin Dissociation Curve

25. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question Respiratory acidosis causes the oxyhemoglobin dissociation curve to shift to the: A. Right, a decreased affinity of Hgb for O2 and an increased release of O2 to tissues B. Left, a decreased affinity of Hgb for O2 and an increased release of O2 to tissues C. Right, an increased affinity of Hgb for O2 and a decreased release of O2 to tissues D. Left, an increased affinity of Hgb for O2 and a decreased release of O2 to tissues

26. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer A. Right, a decreased affinity of Hgb for O2 and an increased release of O2 to tissues. Rationale: Hemoglobin binds less readily with oxygen when there is a decreased pH, increased CO2, elevated body temperature, and elevated 2,3-DPG. This results in a shift to the right of the oxyhemoglobin dissociation curve and a decreased affinity of hemoglobin for oxygen and an increased release of oxygen to tissues. A shift to the left of the curve would result in the opposite effects. Causes of a left shift include an increased pH, decreased CO2, and hypothermia.

27. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question When the central chemoreceptors are activated, the client would: A. Increase the rate and depth of respirations to inhale more oxygen B. Decrease the rate and depth of respirations to retain more CO2 C. Hypoventilate to blow off retained CO2 D. Hyperventilate to blow off retained CO2

28. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer D. Hyperventilate to blow off retained CO2 Rationale: Central chemoreceptors are activated to get rid of retained CO2 by hyperventilation to blow off the excess CO2. Peripheral chemoreceptors are activated when there is a low oxygen tension; this results in an increased rate and depth to get more oxygen into the system.