1. Chapter 22: Respiratory System

2. Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
Lesson 22.1 Objectives
Describe the structure and functions of the organs of the respiratory system.
Trace the movement of air from the nostrils to the alveoli.
Describe the role of pulmonary surfactants.
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

3. Structure: Organs of the Respiratory System
Upper respiratory tract: respiratory organs located outside chest cavity
Lower respiratory tract: organs located inside the chest cavity
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

4. Structure: Organs of the Respiratory System (cont’d.)
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

5. Upper Respiratory System
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

6. Upper Respiratory System (cont’d.)
Nose: external portion forms part of the face
Nasal cavities: internal portion of the nose
Nasal septum: partition between right and left halves of the nasal cavities
Nostrils: two openings in the nasal cavities through which air enters; also called nares
Olfactory organs: receptor cells for the sense of smell
Nasal conchae: three bony projections on the lateral walls of the nasal cavities
Paranasal sinuses: drainage openings
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

7. Upper Respiratory System (cont’d.)
Pharynx: conducts food to esophagus and air to larynx
Nasopharynx: upper
Oropharynx: middle
Laryngopharynx: lower
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

8. Upper Respiratory System (cont’d.)
Larynx: voicebox; triangular structure of cartilage, muscles, and ligaments
Thyroid cartilage
Epiglottis
Vocal cords
Glottis
Three functions:
Passageway for air
Produce sound
Prevents objects from entering breathing structures
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

9. Upper Respiratory System (cont’d.)
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

10. Upper Respiratory System (cont’d.)
Trachea: windpipe; splits into left and right bronchi in thoracic cavity
Carina: point at which trachea splits at the manubriosternal junction
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

11. Lower Respiratory System
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

12. Lower Respiratory System (cont’d.)
Bronchial tree:
Bronchi
Bronchioles
Alveoli
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

13. Lower Respiratory System (cont’d.)
Bronchi: formed from lower trachea dividing into two parts, left and right bronchi
Primary bronchi: enter lungs at the hilus, branch into secondary bronchi
Secondary bronchi: branch into smaller tertiary bronchi
Tertiary bronchi
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

14. Lower Respiratory System (cont’d.)
Bronchioles: smaller tubes formed from repeated division of bronchi; regulate flow of air to the alveoli
Alveolar ducts: formed from the division of bronchioles
Alveoli: small grape-like structures at the end of the alveolar ducts; tiny air sacs
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

15. Lower Respiratory System (cont’d.)
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

16. Lower Respiratory System (cont’d.)
Lungs: large, soft, cone-shaped organs; occupy most of the thoracic cavity
Right lung: three lobes
Superior
Middle
Inferior
Left lung: two lobes
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

17. Lower Respiratory System (cont’d.)
Pleura: continuous serous membrane
Visceral pleura
Parietal pleura
Pleural cavity: space between visceral pleura and parietal pleura
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

18. Lower Respiratory System (cont’d.)
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

19. Collapsed and Expanded Lungs
Lungs collapse because of:
Elastic recoil
Surface tension
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

20. Collapsed and Expanded Lungs (cont’d.)
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

21. Collapsed and Expanded Lungs (cont’d.)
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

22. Collapsed and Expanded Lungs (cont’d.)
Lungs expand due to negative pressure within the intrapleural space
Atmospheric pressure
Intrapulmonic pressure
Intrapleural pressure
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

23. Collapsed and Expanded Lungs (cont’d.)
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

24. Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
Lesson 22.2 Objectives
Describe the relationship of Boyle’s law to ventilation.
Explain how respiratory muscles affect thoracic volume.
List three conditions that make the alveoli well-suited for the exchange of oxygen and carbon dioxide.
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

25. Lesson 22.2 Objectives (cont’d.)
List lung volumes and capacities
Explain the neural and chemical control of respiration.
Describe common variations and abnormalities of breathing.
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

26. Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
Respiratory Function
Three steps of respiration:
Ventilation, or breathing
Exchange of oxygen and carbon dioxide
Transport of oxygen and carbon dioxide by the blood
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

27. Respiratory Function (cont’d.)
Ventilation: breathing; two phases are inhalation and exhalation
Respiratory cycle: one inhalation and one exhalation
Boyle’s law: relationship between pressure and volume
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

28. Respiratory Function (cont’d.)
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

29. Respiratory Function (cont’d.)
Boyle’s law and ventilation:
Inhalation is due to an increase in the thoracic and lung volumes
As lung volume increases, intrapulmonic pressure decreases, causing air to move into the lungs (inhalation)
Exhalation is due to a decrease in thoracic and lung volumes
As lung volume decreases, intrapulmonic pressure increases and air moves out of the lungs (exhalation)
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

30. Respiratory Function (cont’d.)
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

31. Respiratory Function (cont’d.)
Respiratory muscles: contract and relax to change thoracic volume
Diaphragm: dome-shaped muscle that forms the floor of the thoracic cavity; chief muscle of inspiration
Intercostal muscles: located between the ribs
Accessory muscles of respiration: used to move the rib cage farther during exertion and for forced exhalation
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

32. Respiratory Function (cont’d.)
Motor nerves that supply the respiratory muscles:
Phrenic nerve
Intercostal nerves
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

33. Respiratory Function (cont’d.)
Three conditions make alveoli well suited for gas exchange:
Large surface area
Thin alveolar and pulmonary capillary walls
Short distance between the alveoli and pulmonary capillaries
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

34. Respiratory Function (cont’d.)
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

35. Respiratory Function (cont’d.)
Partial pressure: amount of pressure each gas contributes to the total pressure
Oxyhemoglobin: molecule formed from oxygen and hemoglobin bond
Carbaminohemoglobin: molecule formed from carbon dioxide and hemoglobin bond
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

36. Respiratory Function (cont’d.)
Pulmonary volumes:
Tidal volume: 500 ml
Inspiratory reserve volume: 3000 ml
Expiratory reserve volume: 1100 ml
Residual volume: 1200 ml
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

37. Respiratory Function (cont’d.)
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

38. Respiratory Function (cont’d.)
Pulmonary capacities:
Vital capacity: 4600 ml
Functional residual capacity: 2300 ml
Total lung capacity: 5800 ml
Anatomical dead space: 150 ml
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

39. Respiratory Function (cont’d.)
Control of respiration
Nervous mechanisms
Brain stem: medulla oblongata (most important) and pons
Higher centers: cerebral cortex and hypothalamus
Chemical mechanisms detect changes in blood concentrations of CO2 and H+
Central chemoreceptors
Peripheral chemoreceptors: aortic and carotid bodies
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

40. Respiratory Function (cont’d.)
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

41. Respiratory Function (cont’d.)
Variations of respiration:
Normal respiratory rate: body is at rest
Increased respiratory rate: associated with exercise, anxiety, increases in metabolic rate, and overstimulation of the respiratory center in the brain
Decreased respiratory rate: associated with relaxation, decreases in metabolic rate, depression of the respiratory center in the brain
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

42. Respiratory Function (cont’d.)
Hyperventilation: increase in the rate and depth of respirations causing excess exhalation of carbon dioxide
Hypoventilation: decrease in the amount of air entering the alveoli causing insufficient oxygen and excessive carbon dioxide levels in the blood
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

43. Common Respiratory Terms
Apnea: temporary cessation of breathing
Dyspnea: difficult or labored breathing
Tachypnea: rapid breathing
Eupnea: normal, quiet breathing
Orthopnea: difficulty in breathing that is relieved by a sitting-up position
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

44. Common Respiratory Terms (cont’d.)
Cheyne-Stokes respirations: irregular breathing pattern characterized by a series of shallow breaths that gradually increase in depth and rate
Kussmaul breathing: increase in rate and depth of respiration stimulated by acidosis
Cyanosis: bluish color of the skin or mucous membrane due to a low concentration of oxygen in the blood
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.

45. Common Respiratory Terms (cont’d.)
Hypoxia: abnormally low concentration of oxygen in the tissues
Hypoxemia: abnormally low concentration of oxygen in the blood
Hypercapnia: abnormally high concentration of carbon dioxide in the blood
Hypocapnia: abnormally low concentration of carbon dioxide in the blood
Copyright © 2007 by Saunders, an imprint of Elsevier Inc.
All rights reserved.