The Respiratory System

1. The Respiratory System

2. What are the primary functions of the respiratory system?

3. Oxygen • Is obtained from the air by diffusion across delicate exchange surfaces of lungs • Is carried to cells by the cardiovascular system which also returns carbon dioxide to the lungs

4. 5 Functions of the Respiratory System • Provides extensive gas exchange surface area between air and circulating blood • Moves air to and from exchange surfaces of lungs

5. 5 Functions of the Respiratory System • Protects respiratory surfaces from outside environment • Produces sounds-speaking, singing • Participates in olfactory sense

6. Components of the Respiratory System Figure 23–1

7. Organization of the Respiratory System • The respiratory system is divided into the upper respiratory system, above the larynx, and the lower respiratory system, from the larynx down

8. The Respiratory Tract • Consists of a conducting portion: • from nasal cavity to terminal bronchioles • Consists of a respiratory portion: • the respiratory bronchioles and alveoli - Are air-filled pockets within the lungs • where all gas exchange takes place

9. The Respiratory Epithelium Figure 23–2

10. Alveolar sac Alveoli Figure 23–2

11. The Respiratory Epithelium • For gases to exchange efficiently: • alveoli walls must be very thin (< 1 µm) • surface area must be very great (about 35 times the surface area of the body)

12. The Respiratory Mucosa • Consists of: • an epithelial layer • an areolar layer • Lines conducting portion of respiratory system

13. The Lamina Propria • Underlies areolar tissue • In the upper respiratory system, trachea, and bronchi: • contains mucous glands that secrete onto epithelial surface • In the conducting portion of lower respiratory system: • contains smooth muscle cells that encircle lumen of bronchioles

14. How are delicate respiratory exchange surfaces protected from pathogens, debris, and other hazards?

15. The Respiratory Defense System • Consists of a series of filtration mechanisms • Removes particles and pathogens

16. Components of the Respiratory Defense System (1 of 2) • Goblet cells and mucous glands: • produce mucus that bathes exposed surfaces • Cilia: • sweep debris trapped in mucus toward the pharynx (mucus escalator)

17. Components of the Respiratory Defense System (2 of 2) • Filtration in nasal cavity removes large particles • Alveolar macrophages engulf small particles that reach lungs

18. What are the organs of the upper respiratory system and their functions?

19. The Upper Respiratory System Figure 23–3

20. The Nose • Air enters the respiratory system: • through nostrils or external nares • into nasal vestibule • Nasal hairs: • are in nasal vestibule • are the first particle filtration system

21. The Nasal Cavity • The nasal septum: • divides nasal cavity into left and right • Mucous secretions from paranasal sinus and tears: • clean and moisten the nasal cavity • Superior portion of nasal cavity is the olfactory region: • provides sense of smell

22. Air Flow • From vestibule to internal nares: • through superior, middle, and inferior meatuses

23. Meatuses • Constricted passageways that produce air turbulence: • warm and humidify incoming air • trap particles

24. The Palates • Hard palate: • forms floor of nasal cavity • separates nasal and oral cavities • Soft palate: • extends posterior to hard palate • divides superior nasopharynx from lower pharynx

25. The Nasal Mucosa • Warm and humidify inhaled air for arrival at lower respiratory organs • Breathing through mouth bypasses this important step

26. The Pharynx • A chamber shared by digestive and respiratory systems • Extends from internal nares to entrances to larynx and esophagus

27. Divisions of the Pharynx • Nasopharynx • Oropharynx • Laryngopharynx

28. The Nasopharynx • Superior portion of the pharynx • Contains pharyngeal tonsils and openings to left and right auditory tubes

29. The Oropharynx • Middle portion of the pharynx • Communicates with oral cavity

30. The Laryngopharynx • Inferior portion of the pharynx • Extends from hyoid bone to entrance to larynx and esophagus

31. What is the structure of the larynx and its role in normal breathing and production of sound?

32. Anatomy of the Larynx Figure 23–4

33. Cartilages of the Larynx • 3 large, unpaired cartilages form the larynx: • the thyroid cartilage • the cricoid cartilage • the epiglottis

34. The Thyroid Cartilage • Also called the Adam’s apple • Is a hyaline cartilage • Forms anterior and lateral walls of larynx • Ligaments attach to hyoid bone, epiglottis, and laryngeal cartilages

35. The Cricoid Cartilage • Is a hyaline cartilage • Form posterior portion of larynx • Ligaments attach to first tracheal cartilage • Articulates with arytenoid cartilages

36. The Epiglottis • Composed of elastic cartilage • Ligaments attach to thyroid cartilage and hyoid bone

37. Cartilage Functions • Prevents entry of food and liquids into respiratory tract • During swallowing: • the larynx is elevated • the epiglottis folds back over glottis • Thyroid and cricoid cartilages support and protect: • the glottis • the entrance to trachea

38. The Glottis Figure 23–5

39. Sound Production • Air passing through glottis: • vibrates vocal folds • produces sound waves Sound Variation • Sound is varied by: • tension on vocal folds • voluntary muscles (position arytenoid cartilage relative to thyroid cartilage)

40. Speech • Is produced by: • phonation: • sound production at the larynx • articulation: • modification of sound by other structures

41. What is the structure of airways outside the lungs?

42. Anatomy of the Trachea Figure 23–6

43. The Trachea • Also called the windpipe • Extends from the cricoid cartilage into mediastinum • where it branches into right and left pulmonary bronchi

44. The Tracheal Cartilages • 15–20 tracheal cartilages: • strengthen and protect airway • discontinuous where trachea contacts esophagus • Ends of each tracheal cartilage are connected by: • an elastic ligament and trachealis muscle

45. The Primary Bronchi • Right and left primary bronchi: • separated by an internal ridge (the carina) The Right Primary Bronchus • Is larger in diameter than the left • Descends at a steeper angle

46. Hilus Structure of Primary Bronchi • Where pulmonary nerves, blood vessels, and lymphatics enter lung • Anchored in meshwork of connective tissue • Each primary bronchus: • travels to a groove (hilus) along medial surface of the lung

47. What are the superficial anatomy of the lungs, the structure of a pulmonary lobule, and the functional anatomy of the alveoli?

48. Gross Anatomy of the Lungs Figure 23–7

49. The Lungs • Left and right lungs: • are in left and right pleural cavities • The base: • inferior portion of each lung rests on superior surface of diaphragm

50. The Right Lung • Has 3 lobes: • superior, middle, and inferior • separated by horizontal and oblique fissures