The Respiratory System Ch 22 Human Anatomy Sonya Schuh-Huerta, Ph.D.

1. The Respiratory System Ch 22 Human Anatomy Sonya Schuh-Huerta, Ph.D. Leonardo Da Vinci

2. The Upper Respiratory Tract Cribriform plate of ethmoid bone Frontal sinus Sphenoid sinus Nasal cavity Posterior nasal aperture Nasal conchae (superior, middle and inferior) Nasopharynx Pharyngeal tonsil Nasal meatuses (superior, middle, and inferior) Opening of pharyngotympanic tube Nasal vestibule Nostril Uvula Oropharynx Hard palate Palatine tonsil Soft palate Isthmus of the fauces Tongue Lingual tonsil Laryngopharynx Hyoid bone Larynx Epiglottis Vestibular fold Esophagus Thyroid cartilage Vocal fold Trachea Cricoid cartilage Thyroid gland

3. Organs of the Respiratory System Nasal cavity Oral cavity Pharynx Nostril Left main (primary) bronchus Larynx Trachea Bronchi Carina of trachea Alveoli Right main (primary) bronchus Left lung Right lung Diaphragm Parietal pleura

4. Bronchi in the Conducting Zone Superior lobe of right lung Trachea Superior lobe of left lung Left main (primary) bronchus Lobar (secondary) bronchus Segmental (tertiary) bronchus Inferior lobe of left lung Middle lobe of right lung Inferior lobe of right lung (a) The branching of the bronchial tree

5. Alveoli Alveolar duct Respiratory bronchioles Alveolar duct Terminal bronchiole Alveolar sac (a) Structures of the Respiratory Zone

6. Alveoli & the Respiratory Membrane Terminal bronchiole Respiratory bronchiole Smooth muscle Elastic fibers Alveolus Capillaries (a) Diagrammatic view of capillary-alveoli relationships

7. Anatomy of Alveoli & the Respiratory Membrane Red blood cell Nucleus of type I (squamous epithelial) cell Alveolar pores Capillary O2 Capillary CO2 Alveolus Macrophage Endothelial cell nucleus Alveolus Alveolar epithelium Respiratory membrane Fused basement membranes of the alveolar epithelium and the capillary endothelium Red blood cell in capillary Type I cell of alveolar wall Capillary endothelium Alveoli (gas-filled air spaces) Type II (surfactant- secreting) cell (c) Detailed anatomy of the respiratory membrane

8. The Respiratory System • Basic functions of the respiratory system • Supplies body with oxygen • Disposes of carbon dioxide • 4 processes involved in respiration: • Pulmonary ventilation • External respiration • Transport of respiratory gases • Internal respiration

9. Functional Anatomy of the Respiratory System • Respiratory organs • Nose, nasal cavity, & paranasal sinuses • Pharynx, larynx, & trachea • Bronchi & smaller branches • Lungs & alveoli

10. Organs of the Respiratory System • Divided into • Conducting zone • Respiratory zone

11. The Nose • Provides an airway for respiration • Moistens & warms air (humidifies air) • Filters inhaled air • Resonating chamber for speech • Houses olfactory receptors (olfaction)

12. Frontal bone Epicranius, frontal belly Nasal bone Septal cartilage Root and bridge of nose Maxillary bone (frontal process) Lateral process of septal cartilage Dorsum nasi Minor alar cartilages Ala of nose Dense fibrous connective tissue Apex of nose Naris (nostril) Major alar cartilages Philtrum (a) Surface anatomy (b) External skeletal framework The Nose • Size variation due to differences in nasal cartilages • Skin is thin  contains many sebaceous glands

13. The Nasal Cavity • External nares  nostrils • Divided by nasal septum • Continuous with nasopharynx

14. Nasal Cavity • 2 types of mucous membrane: • Olfactory mucosa • Near roof of nasal cavity • Houses olfactory receptors • Respiratory mucosa • Lines nasal cavity • Pseudostratified ciliated columnar epithelium

15. The Upper Respiratory Tract Cribriform plate of ethmoid bone Frontal sinus Sphenoid sinus Nasal cavity Posterior nasal aperture Nasal conchae (superior, middle and inferior) Nasopharynx Pharyngeal tonsil Nasal meatuses (superior, middle, and inferior) Opening of pharyngotympanic tube Nasal vestibule Nostril Uvula Oropharynx Hard palate Palatine tonsil Soft palate Isthmus of the fauces Tongue Lingual tonsil Laryngopharynx Hyoid bone Larynx Epiglottis Vestibular fold Esophagus Thyroid cartilage Vocal fold Trachea Cricoid cartilage Thyroid gland

16. Respiratory Mucosa • Consists of: • Pseudostratified ciliated columnar epithelium • Goblet cells within epithelium • Underlying layer of lamina propria • Cilia move contaminated mucus posteriorly

17. Nasal Conchae • Superior & middle nasal conchae • Part of the ethmoid bone • Inferior nasal conchae • Separate bone • Project medially from the lateral wall of the nasal cavity • Particulate matter: • Deflected to mucus-coated surfaces

18. The Pharynx • Funnel-shaped passageway • Connects nasal cavity & mouth • Divided into 3 sections by location: • Nasopharynx • Oropharynx • Laryngopharynx • Type of mucosal lining changes along its length

19. The Nasopharynx • Superior to the point where food enters • Only an air passageway • Closed off during swallowing • Pharyngeal tonsil (adenoids) • Located on posterior wall • Destroys pathogens that enter • Contains the opening to the pharyngotympanic tube (auditory or eustachian tube) • Tubal tonsil • Provides some protection from infection

20. The Oropharynx • Arch-like entrance-way  fauces • Extends from soft palate to epiglottis • Epithelium • Stratified squamous epithelium • 2 types of tonsils in the oropharynx • Palatine tonsils in lateral walls of the fauces • Lingual tonsils covers the posterior surface • of the tongue

21. The Laryngopharynx • Passageway for both food & air • Epithelium • Stratified squamous epithelium • Continuous with the esophagus & larynx

22. The Larynx • 3 functions  • Voice production • Provides an open airway • Routes air & food into the proper channels • Superior opening (epiglotis) is: • Closed during swallowing • Open during breathing

23. 9 Cartilages of the Larynx • Thyroid cartilage • Shield-shaped, forms laryngeal prominence (= Adam’s apple) • 3 pairs of small cartilages • Arytenoid cartilages • Corniculate cartilages • Cuneiform cartilages • Epiglottis • Tips inferiorly during swallowing

24. The Larynx • Vocal ligaments of the larynx • Vocal folds (= true vocal cords) • Function in sound production • Vestibular folds (= false vocal cords) • No role in sound production • Epithelium of the larynx: • Stratifiedsquamous  superior portion • Pseudostratified ciliated columnar  inferior portion

25. Anatomy of the Larynx Body of hyoid bone Laryngeal prominence (Adam’s apple) Cricoid cartilage Sternal head Clavicular head Sternocleidomastoid Clavicle Jugular notch (a) Surface view Epiglottis Thyrohyoid membrane Body of hyoid bone Thyroid cartilage Laryngeal prominence (Adam’s apple) Cricothyroid ligament Cricoid cartilage Cricotracheal ligament Tracheal cartilages (b) Anterior view

26. Anatomy of the Larynx Epiglottis Hyoid bone Thyrohyoid membrane Corniculate cartilage Arytenoid cartilage Thyroid cartilage Cricoid cartilage Glottis Tracheal cartilages (c) Photograph of cartilaginous framework of the larynx, posterior view Epiglottis Thyrohyoid membrane Body of hyoid bone Thyrohyoid membrane Cuneiform cartilage Fatty pad Vestibular fold (false vocal cord) Corniculate cartilage Arytenoid cartilage Thyroid cartilage Arytenoid muscle Vocal fold (true vocal cord) Cricoid cartilage Cricothyroid ligament Cricotracheal ligament Tracheal cartilages (d) Sagittal section (anterior on the right)

27. Movements of the Vocal Cords Anterior Thyroid cartilage Cricoid cartilage Vocal ligaments of vocal cords Glottis Lateral cricoarytenoid muscle Arytenoid cartilage Corniculate cartilage Posterior cricoarytenoid muscle Posterior Base of tongue Epiglottis Vestibular fold (false vocal cord) Vocal fold (true vocal cord) Glottis Inner lining of trachea Cuneiform cartilage Corniculate cartilage (a) Vocal folds in closed position; closed glottis (b) Vocal folds in open position; open glottis

28. The Larynx • Voice production • Length of the vocal folds changes with pitch • Loudness depends on the force of air across the vocal folds • Sphincter function of the larynx • Valsalva’s maneuver straining • Innervation of the larynx • Recurrent laryngeal nerves (branch of vagus)

29. The Trachea • Descends into the mediastinum • C-shaped cartilage rings keep airway open! • Carina • Marks where trachea divides into 2 primary bronchi • Epithelium  • Pseudostratified ciliated columnar epithelium • ~remember this?

30. The Trachea Mucosa Pseudostratified ciliated columnar epithelium Lamina propria (connective tissue) Submucosa Seromucous gland in submucosa Posterior Hyaline cartilage Mucosa Esophagus (b) Photomicrograph of the tracheal wall (250) Submucosa Trachealis muscle Seromucous gland in submucosa Lumen of trachea Hyaline cartilage Adventitia Anterior (a) Cross section of the trachea and esophagus

31. Bronchi in the Conducting Zone • Bronchial tree • Extensively branching respiratory passageways • Primary bronchi (main bronchi) • Largest bronchi • Right main primary bronchi • Wider & shorter than the left • Right lung also bigger than the left

32. Bronchi in the Conducting Zone Superior lobe of right lung Trachea Superior lobe of left lung Left main (primary) bronchus Lobar (secondary) bronchus Segmental (tertiary) bronchus Inferior lobe of left lung Middle lobe of right lung Inferior lobe of right lung (a) The branching of the bronchial tree

33. Bronchi in the Conducting Zone • Secondary (lobar) bronchi • Three on the right • Two on the left • Tertiary (segmental) bronchi • Branch into each lung segment • Bronchioles • Little bronchi, less than 1 mm in diameter • Terminal bronchioles • Less than 0.5 mm in diameter

34. Bronchi in the Conducting Zone Mucosa Pseudostratified epithelium Lamina propria Fibromusculo- cartilaginous layer Lumen Cartilage plate Smooth muscle (b) Photomicrograph of a bronchus (13)

35. Changes in Tissue Along Conducting Pathways • Supportive connective tissues change • C-shaped rings replaced by cartilage plates • Epithelium changes • First, pseudostratified ciliated columnar • Replaced by simple columnar, then simple cuboidal epithelium • Smooth muscle becomes important: • Airways widen with sympathetic stimulation • Airways constrict with parasympathetic stim.

36. Structures of the Respiratory Zone • Consists of air-exchanging structures • Respiratory bronchioles branch from terminal bronchioles • Lead to alveolar ducts • Lead to alveolar sacs

37. Alveoli Alveolar duct Respiratory bronchioles Alveolar duct Terminal bronchiole Alveolar sac (a) Structures of the Respiratory Zone

38. Respiratory bronchiole Alveolar pores Alveolar duct Alveoli Alveolar sac (b) Structures of the Respiratory Zone

39. Structures of the Respiratory Zone • Alveoli • ~300 million alveoli account for tremendous surface area of the lungs! • Surface area of alveoli is ~140 square meters!!! • Why such a large surface area?

40. Structures of the Respiratory Zone • Structure of alveoli • Type I cells single layer of simple squamous epithelial cells • Surrounded by basal lamina • Alveolar & capillary walls plus their basal lamina form • The Respiratory membrane

41. Anatomy of Alveoli & the Respiratory Membrane Terminal bronchiole Respiratory bronchiole Smooth muscle Elastic fibers Alveolus Capillaries (a) Diagrammatic view of capillary-alveoli relationships

42. Structures of the Respiratory Zone • Structures of alveoli (cont.) • Type II cells scattered among type I cells • Are cuboidal epithelial cells • Secrete surfactant (very important!) • Detergent-like molecule, that reduces surface tension within alveoli (prevents them from collapsing) • Alveolar macrophages also present

43. Anatomy of Alveoli & the Respiratory Membrane Red blood cell Nucleus of type I (squamous epithelial) cell Alveolar pores Capillary O2 Capillary CO2 Alveolus Macrophage Endothelial cell nucleus Alveolus Alveolar epithelium Respiratory membrane Fused basement membranes of the alveolar epithelium and the capillary endothelium Red blood cell in capillary Type I cell of alveolar wall Capillary endothelium Alveoli (gas-filled air spaces) Type II (surfactant- secreting) cell (c) Detailed anatomy of the respiratory membrane

44. The Respiratory Zone • Features of alveoli • Surrounded by elastic fibers • Interconnect by way of alveolar pores • Internal surfaces • A site for free movement of alveolar macrophages

45. Gross Anatomy of the Lungs • Major landmarks of the lungs • Apex, base, hilum, & root • Left lung • Superior & inferior lobes • Right lung • Superior, middle, & inferior lobes

46. Gross Anatomy of the Lungs Anterior View of Thoracic Structures Intercostal muscle Rib Apex of lung Parietal pleura Lung Pleural cavity Visceral pleura Pulmonary artery Trachea Thymus Apex of lung Left main bronchus Left superior lobe Left superior lobe Right superior lobe Oblique fissure Oblique fissure Pulmonary vein Horizontal fissure Left inferior lobe Right middle lobe Left inferior lobe Impression of heart Oblique fissure Right inferior lobe Oblique fissure Hilum Heart (in mediastinum) Aortic impression Diaphragm Cardiac notch Lobules Base of lung (b) Photograph of medial view of the left lung (a) Anterior view. The lungs flank mediastinal structures laterally.

47. Bronchial Tree Right lung Left lung Right superior lobe (3 segments) Left superior lobe (4 segments) Right middle lobe (2 segments) Right inferior lobe (5 segments) Left inferior lobe (5 segments)

48. Blood Supply & Innervation of the Lungs • Pulmonary arteries • Deliver oxygen-poor blood to the lungs • Pulmonary veins • Carry oxygenated blood to the heart • Innervation • Sympathetic, parasympathetic, & visceral sensory fibers • Parasympathetic  constrict airways • Sympathetic  dilate airways

49. Transverse Cut Through Lungs Posterior Esophagus (in mediastinum) Vertebra Root of lung at hilum Right lung Left main bronchus Left pulmonary artery Parietal pleura Left pulmonary vein Visceral pleura Left lung Pleural cavity Thoracic wall Pulmonary trunk Pericardial membranes Heart (in mediastinum) Anterior mediastinum Sternum Anterior (d) Transverse section through the thorax, viewed from above. Lungs, pleural membranes, and major organs in the mediastinum are shown.

50. The Pleurae (review) • A double-layered sac surrounding each lung • Parietal pleura • Visceral pleura • Pleural cavity • Potential space between the visceral & parietal pleurae • Pleurae help divide the thoracic cavity • Central mediastinum • 2 lateral pleural compartments