1. The Respiratory System
Basic functions of the respiratory system
Breathing (Pulmonary Ventilation) – movement of air in and out of the lungs
Inhalation (inspiration) draws gases into the lungs.
Exhalation (expiration) forces gases out of the lungs.
Gas Conditioning – as gases pass through the nasal cavity and paransal sinuses, inhaled air becomes turbulent. The gases in the air are
• warmed to body temperature
• humidified
• cleaned of particulate matter
Gas Exchange - respiration
• Supplies body with oxygen
• Disposes of carbon dioxide
Produces Sounds
Protects respiratory surfaces
Site for olfactory sensation

2. Respiration Respiration – four distinct processes must happen
Pulmonary ventilation – moving air into and out of the lungs
External respiration – gas exchange between the lungs and the blood
Transport – transport of oxygen and carbon dioxide between the lungs and tissues
Internal respiration – gas exchange between systemic blood vessels and tissues

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

4. Organs of the Respiratory System
Figure 21.1

5. Respiratory System Consists of
Respiratory muscles – diaphragm and other muscles that promote ventilation
Respiratory zone – site of external respiration – respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.
Conducting zones
Provides rigid conduits for air to reach the sites of gas exchange
Includes nose, nasal cavity, pharynx, trachea
Air passages undergo 23 orders of branching in the lungs

6. The Nose Provides an airway for respiration Moistens and warms air
Filters inhaled air
Resonating chamber for speech
Houses olfactory receptors
Skin is thin – contains many sebaceous glands

7. The Nasal Cavity External nares – nostrils Divided by – nasal septum
Vestibule - anterior opening
Continuous with nasopharynx
Two types of mucous membrane
Olfactory mucosa - Near roof of nasal cavity, houses olfactory (smell) receptors
Respiratory mucosa - Lines nasal cavity
Epithelium is pseudostratified ciliated columnar
Goblet cells within epithelium
Underlying layer of lamina propria has glands that contribute to the mucus layer and blood vessels that warm the air.
Cilia move contaminated mucus posteriorly

8. Nasal Cavity

9. Nasal Conchae
3 paired bony projections along the lateral walls of the nasal cavity
Superior and middle nasal conchae - part of the ethmoid bone
Inferior nasal conchae - separate bone
Function - Particulate matter deflected to mucus-coated surfaces

10. The Paranasal Sinuses
Figure 7.11a, b

11. The Pharynx Funnel-shaped passageway Connects nasal cavity and mouth
Shared by the digestive and respiratory systems
Divided into three sections by location
Nasopharynx – superior portion,
Oropharynx – continuous with the oral cavity
Laryngopharynx – between the hyoid bone and the esophagus
Type of mucosal lining changes along its length

12. The Nasopharynx Superior to the point where food enters
Only an air passageway
Closed off during swallowing
Epithelium consists of ciliated pseudostratified epithelium that moves mucus

13. The Oropharynx Arch-like entranceway – fauces
Extends from soft palate to the epiglottis
Epithelium - stratified squamous epithelium
Two types of tonsils in the oropharynx
Palatine tonsils – in the lateral walls of the fauces
Lingual tonsils – covers the posterior surface of the tongue

14. The Laryngopharynx Passageway for both food and air
Epithelium - stratified squamous epithelium
Continuous with the esophagus and larynx

15. The Larynx Prevent food and drink from entering the trachea
Passageway for air
Produces Sound
It connects the pharynx to the trachea
Epithelium of the larynx
Stratified squamous – superior portion
Pseudostratified ciliated columnar – inferior portion

16. Nine Cartilages of the Larynx
Thyroid cartilage - shield-shaped, forms laryngeal prominence (Adam’s apple)
Three pairs of small cartilages
Arytenoid cartilages
Corniculate cartilages
Cuneiform cartilages
Epiglottis - tips inferiorly during swallowing

17. The Larynx Vocal ligaments of the larynx
Vocal folds (true vocal cords) - act in sound production
Vestibular folds (false vocal cords) - no role in sound production
Voice production
Length of the vocal folds changes with pitch
Loudness depends on the force of air across the vocal folds

18. The Trachea Descends into the mediastinum
C-shaped cartilage rings keep airway open
Carina - marks where trachea divides into two primary bronchi
Epithelium - pseudostratified ciliated columnar

19. The Trachea
Figure 21.7a, b

20. Bronchi in the Conducting Zone
Bronchial tree - extensively branching respiratory passageways
Primary bronchi (main bronchi)
Largest bronchi
Right main bronchi - wider and shorter than the left
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

21. Tissue Composition of Conducting Zone
Changes along pathway
Supportive connective tissues change
C-shaped rings – trachea, primary bronchi
Replaced by cartilage plates, secondary & tertiary bronchi
Epithelium changes
First, pseudostratified ciliated columnar – trachea
Replaced by simple columnar - bronchi
Then simple cuboidal epithelium - bronchioles and terminal bronchioles
Smooth muscle becomes important at the bronchioles - controlled by the ANS (bronchoconstriction and bronchodilation).

22. Lobes and Surfaces of the lungs
Right lung has three lobes
Left lung has two lobes
Concavity on medial surface = cardiac notch
Bronchi enter the lungs at the hilus

23. The Pleurae A double-layered sac surrounding each lung Parietal pleura
Visceral pleura
Pleural cavity - potential space between the visceral and parietal pleurae
Pleurae help divide the thoracic cavity
Central mediastinum
Two lateral pleural compartments

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

25. Structures of the Respiratory Zone
Figure 21.9b

26. Features Of Alveoli Alveoli cell types
Type I cells site of gas exchangeand
Type II cells - secrete surfactant
Macrophages
Surrounded by basal laminae and elastic fibers
Interconnect by way of alveolar pores
Internal surfaces - site for free movement of alveolar macrophages
Figure 21.10b