Chapter 23, part 1

1. Chapter 23, part 1 The Respiratory System

2. SECTION 23-1The Respiratory System: An Introduction

3. Learning Objectives • Describe the primary functions of the respiratory system • Identify the organs of the respiratory system and describe their functions • Define and compare the processes of external and internal respiration

4. Learning Objectives • Summarize the physical principles governing the movement of air into the lungs and the diffusion of gases into the blood • Explain the important structural features of the respiratory membrane • Describe how oxygen and carbon dioxide are picked up, transported and released in the blood

5. Functions of the respiratory system • Gas exchange between air and circulating blood • Moving air from the exchange surface of the lungs • Protection of respiratory surfaces • Production of sound • Provision for olfactory sensations

6. Organization of the respiratory system • Upper respiratory system • Nose, nasal cavity, paranasal sinuses, pharynx • Lower respiratory system • Larynx, trachea, bronchi, bronchioles, alveoli

7. Figure 23.1 The Components of the Respiratory System Figure 23.1

8. The Respiratory tract • Conducting passageways carrying air to and from the alveoli • Upper respiratory passages filter and humidify incoming air • Lower passageways include delicate conduction passages and alveolar exchange surfaces

9. Respiratory Mucosa • Respiratory epithelium and underlying connective tissue • Respiratory membrane, supported by lamina propria, changes along tract • Lines conducting portion of respiratory tract • Protected from contamination by respiratory defense system

10. Figure 23.2 The Respiratory Epithelium of the Nasal Cavity and Conducting System Figure 23.2

11. SECTION 23-2The Upper Respiratory System

12. The nose and nasal cavity consists of: • External nares • Nasal cavity • Vestibule • Superior, middle and inferior meatuses • Hard and soft palates • Internal nares • Nasal mucosa

13. Figure 23.3 The Nose, Nasal Cavity, and Pharynx Figure 23.3a, b

14. Figure 23.3 The Nose, Nasal Cavity, and Pharynx Figure 23.3c

15. The pharynx • Shared by the digestive and respiratory systems • Divided into three sections: • Nasopharynx – superior portion • Oropharynx – continuous with the oral cavity • Laryngopharynx – between the hyoid bone and the esophagus

16. SECTION 23-3The Larynx

17. The larynx • Air passes through the glottis on the way to the lungs • Larynx protects the glottis • Cartilages of the larynx • Three large cartilages • Thyroid, cricoid, and epiglottis • Paired cartilages • Arytenoids, corniculate, and cuneiform

18. Folds of the larynx • Inelastic vestibular folds • Delicate vocal folds

19. Figure 23.4 The Anatomy of the Larynx Figure 23.4

20. Sound production • Air passing through the glottis vibrates the vocal folds producing sound waves • Pitch depends on conditions of vocal folds • Diameter • Length • Tension

21. Figure 23.5 The Glottis Figure 23.5a, b

22. The laryngeal musculature • Muscles of the neck and pharynx position and stabilize the larynx • When swallowing,these muscles • Elevate the larynx • Bend the epiglottis over the glottis • Intrinsic muscles control tension on the vocal folds and open the glottis

23. SECTION 23-4The Trachea and Primary Bronchi

24. The trachea • Extends from the sixth cervical vertebra to the fifth thoracic vertebra • A tough, flexible tube running from the larynx to the bronchi • Held open by C-shaped tracheal cartilages in submucosa • Mucosa is similar to the nasopharynx

25. Figure 23.6 The Anatomy of the Trachea Figure 23.6a, b

26. Figure 23.6 The Anatomy of the Trachea Figure 23.6c

27. The primary bronchi • Trachea branches in the mediastinum into right and left bronchi • Bronchi enter the lungs at the hilus • Root = the connective tissue mass including: • Bronchus • Pulmonary vessels • Nerves

28. SECTION 23-5The Lungs

29. Lobes and surfaces of the lungs • Lobes of the lung are separated by fissures • Right lung has three lobes • Left lung has two lobes • Concavity on medial surface = cardiac notch

30. Figure 23.7 The Gross Anatomy of the Lungs Figure 23.7

31. Figure 23.7 The Gross Anatomy of the Lungs Figure 23.7

32. Figure 23.7 The Gross Anatomy of the Lungs Figure 23.7

33. Figure 23.8 The Relationship between the Lungs and the Heart Figure 23.8

34. The bronchial tree • System of tubes formed from the primary bronchi and their branches • Primary bronchi branch into secondary or lobar bronchi • Secondary bronchus goes to each lobe of the lungs • Secondary bronchi branch into tertiary bronchi • Tertiary bronchi supply air to a single bronchopulmonary segment • Cartilage in walls decrease and smooth muscle increase with branching

35. Figure 23.10 The Bronchi and Lobules of the Lung Figure 23.10a

36. Figure 23.10 The Bronchi and Lobules of the Lung Figure 23.10b

37. The bronchioles • Ultimately branch into terminal bronchioles • Delivers air to a single pulmonary lobule • Terminal bronchiole becomes respiratory bronchioles • Connective tissue of root branches to form interlobar septa

38. Alveolar ducts and alveoli • Respiratory bronchioles end in ducts and sacs • Respiratory exchange surfaces connected to circulatory system via pulmonary circuit PLAY Animation: Lungs Flythrough

39. Figure 23.11 The Bronchioles Figure 23.11

40. Respiratory Membrane • Simple squamous epithelium • Endothelial cell lining an adjacent capillary • Fused basal laminae

41. Cells of the respiratory membrane include • Septal cells • Scattered in respiratory membrane • Produce surfactant • Alveolar Macrophage • Patrol epithelium and engulf foreign particles PLAY Animation: Respiratory Structures

42. Figure 23.12 Alveolar Organization Figure 23.12a-c

43. The blood supply to the lungs • Conducting portions • Receive blood from external carotids, thyrocervical, bronchial arteries • Respiratory exchange surfaces • receive blood from the arteries of the pulmonary circuit • are the source of angiotensin-converting enzyme (ACE) • Pulmonary veins return blood to the left atrium

44. The pleural cavities and pleural membranes • Each lung covered by one pleura • Pleura – serous membranes lining the pleural cavity • Parietal - attaches to the walls of the pleural cavity • Visceral - adheres to the surface of the lungs • Pleural fluid – fills and lubricates the space between the pleura

45. SECTION 23-6An Overview of Respiratory Physiology

46. Respiratory physiology is a series of integrated processes • Internal respiration • Exchange of gases between interstitial fluid and cells • External respiration • Exchange of gases between interstitial fluid and the external environment • The steps of external respiration include: • Pulmonary ventilation • Gas diffusion • Transport of oxygen and carbon dioxide

47. Figure 23.13 An Overview of Key Steps in Respiration Figure 23.13

48. SECTION 23-7Pulmonary Ventilation

49. Pulmonary Ventilation • The physical movement of air into and out of the lungs

50. Air movement • Movement of air depends upon • Boyle’s Law • Pressure and volume inverse relationship • Volume depends on movement of diaphragm and ribs • Pressure and airflow to the lungs • Compliance – an indication of the expandability of the lungs