Respiratory system: Anatomy Part 1

1. Respiratory system: Anatomy Part 1 Lecture 10 Monday, February 5, 2007 Refs. Moore and Agur Chapters 1 and 9, Moore and Dalley Chapter 1, and Ross and Pawlina Chapter 19 or Wheater’s Functional Histology Chapter 12

2. Respiration • Cellular respiration • Reactions in a cell producing ATP • Aerobic respiration requires oxygen (mitochondria, TCA cycle, electron transport) • Mechanical respiration • Process of acquiring oxygen from the atmosphere and excretion of CO2 • Respiratory system includes airways and lungs where gas exchange occurs

3. Components of the respiratory system • Upper respiratory tract • Nasal cavity • Paranasal sinuses (resonance, make head lighter) • Nasopharynx • Functions: filter, humidify, and warm air • Lower respiratory tract • Larynx • Trachea • Bronchi: primary (main), secondary (lobar), tertiary • Bronchioles: many orders…terminal, respiratory • Alveolar ducts • Alveoli or alveolar sacs

4. Nasal cavity • Concha (plural conchae) or turbinates • Thin curved plates of bone • Inferior nasal concha articulates with maxilla, lacrimal, ethmoid and palatine bones • Middle and superior nasal conchae extend from inner wall of ethmoid labyrinth • Meatus refers to an opening or passageway • Inferior nasal meatus, middle nasal meatus, and superior nasal meatus are below respective conchae. • Nasal septum divides nasal cavity vertically • Vomer forms inferior and posterior bony portion.

5. Nasal septum is formed by cartilage, ethmoid bone, and vomer (light green) Netter Pl 34

6. Vomer is on midline (blue) Moore & Agur8.3

7. Pharynx • The palate separates the openings of the alimentary and respiratory tracts. • hard = bone • soft = a soft tissue extension • Tracts “merge/cross” in the pharynx. • Nasopharynx- posterior to the nose and superior to the soft palate. Opening of nasal cavity into nasopharynx is the choana (paired= choanae) • Oropharynx- posterior to the mouth (between the soft palate and pharyngoepiglottic fold) • Laryngopharynx- posterior to the larynx • During swallowing the soft palate acts as a valve to prevent food from entering nasopharynx and the epiglottis closes the larynx.

8. Midsagittal diagram of pharynx Moore 7.51

9. Surface anatomy of larynx Moore & Agur p.622H = hyoidT = thyroid cartilageC = cricoid cartilage1 = first tracheal ring

10. Lateral view of larynx Moore & Agur 9.15a

11. Posterior view of larynx Moore & Agur 9.15b

12. Larynx • Laryngeal skeleton comprises 9 cartilages • Learn the main cartilage components • Epiglottis- elastic cartilage • Thyroid cartilage- hyaline cartilage • Cricoid cartilage- hyaline cartilage • Arytenoid cartilage- hyaline cartilage • Epithelium of the larynx is respiratory except for vocal cords where it is stratified squamous • Muscles including those that tense the vocal chords are skeletal.

13. Number of lung lobes varies with speciesHumans have 5 lobes Moore & Agur

14. Hilus and pleura • Hilus (plural hili) aka hilum (plural hila) • The indented area where vessels and nerves enter and exit an organ. “root” • Specifically for lung: 2 (right and left) where bronchi, arteries and nerves enter and veins and lymphatics exit. • Pleura- the serous membrane forming the outer lining of lung (visceral pleura) and inner lining of the thoracic cavity (parietal pleura). • Moist, lubricated surfaces • Developmentally the primordial coelom is invaginated by the lung; the lining of the cavity in contact with the lung fuses to the lung becoming the visceral pleura. • The parietal pleura is named by the area it lines. • Cervical, costal, mediastinal, diaphragmatic

15. Pleura Moore & Agur 2.16a

16. Mediastinum • Central compartment of of the thoracic cavity • Between the two lung cavities • Lined by pleura • Contains the esophagus, trachea, aorta, heart, etc. • Flexible and mobile • Divisions for description • Superior- above the sternal angle and T4-T5 disk • Inferior-anterior, middle, posterior

17. Mediastinum Moore and Agur 2.20

18. Examination of the lungs • Auscultation • Radiographs • Plain -look for opacities in lung field • Bronchogram- contrast material in airways • Bronchoscopy with fiberoptic endoscope • Visual inspection • Sample collection

19. Radio-opaque material outlines bronchi Moore & Agur

20. BronchoscopyMoore & Agur

21. Dual arterial blood supply to the lungs • Pulmonary • Primary supply, large volume • Deoxygenated blood from the RV • Low pressure, elastic arteries • Bronchial • Branches from the aorta • Supplies the pleura and airway walls • Typical muscular arteries

22. Pulmonary blood supply to the lungs Moore & Agur

23. Bronchial blood supply from aorta to the lungs Moore & Dalley 1.34

24. Venous drainage of the lung • Pulmonary veins (4) empty into left atrium • Main return, large volume • Oxygenated blood • Bronchial veins • Return some of the blood supplied by the bronchial arteries • Azygos on right to vena cava • Hemiazygos from the left to brachiocephalic vein

25. Autonomic nerve supply to the lungs Moore & Dalley 1.36

26. Effects of autonomic stimulation on the lungs • Parasympathetic • bronchoconstriction • Sympathetic • relaxes the airways • reduces glandular secretions

27. Lymphatic drainage of the lungs Moore & Dalley fig. 1.35

28. Anthracosis • Deposition of coal dust (carbon) • Black discoloration especially prominent on pleural surface and in tracheobronchial lymph nodes. • Incidental finding, usually asymptomatic • Found in all urban dwellers and smokers

29. Overview of the respiratory system Wheater’s 12.1

30. Mucosa • General features from lumen to deeper tissue • Mucosa • Epithelium • Lamina propria • Lymphoid tissue • ±muscularis mucosae • Submucosa • glands • Muscular tunic (little muscle in respiratory tract) • Adventitia or serosa

31. Respiratory mucosa in general • Epithelium ranges from tall, ciliated pseudostratified columnar in the trachea to simple squamous in alveoli. • No muscularis mucosae. • Serous and mucous glands in the submucosa. • Cartilage is deep to submucosa.

32. General features of airways • Changes in airways are gradual. • Epithelium becomes lower to squamous • Smooth muscle increases. • No cartilage past tertiary bronchi. • No serous and mucous glands in submucosa past tertiary bronchi

33. Nasal cavity of kitten WFH 12.2

34. Characteristics of nasal mucosa • Numerous goblet cells. • Tall pseudostratified columnar ciliated epithelium. • Highly vascular lamina propria (warms air). • Numerous glands produce watery serous secretions (moisturizes air). • Cilia beat toward pharynx.

35. Nasal mucosa WFH 12.3

36. Trachea: transverse section WFH 12.4