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