1. The Respiratory System
Structures

2. Function of the Respiratory System
Filters, warms, and humidifies the air we breathe
Ensures that oxygen is supplied TO…
…and carbon dioxide is removed FROM…
the body’s cells
Influences speech production
Makes olfaction possible

3. Structures Divided into Upper & Lower Respiratory Tracts
Contains Respiratory mucosa:
Specialized mucous membrane that lines the respiratory tract
Secretes MUCUS
air purification mechanism.
traps irritants such as dust and pollen
Cilia on mucosal cells beat upward, moving mucus to pharynx for removal.

4. Histology: Pseudostratified Ciliated Columnar Epithelium with Goblet Cells (secrete mucus)

5. UPPER RESPIRATORY TRACT
Nose
Nasal cavity
Pharynx
Naso-
Oro-
Laryngo-
Larynx
Mouth
Eustachian tubes

6. Nose Air enters through external nares (nostrils)
Nasal septum separates interior of nose into two cavities (composed of ethmoid, quadrangular cartilage, vomer bone)
Nose warms and moistens inhaled air, contains organs of smell

7. Nasal Cavity Lined by bone, mucous membrane
Ethmoid
Maxilla
Nasal bones
Warms, moistens, cleans air
Cilia trap microorganisms, materials  digestive system
Turbinates/conchae direct air to olfactory gland

8. Sinuses
Frontal, maxillary, sphenoidal, ethmoidal sinuses drain into the nose
Provide resonance for speech
Can become inflamed (sinusitis)

9. CT Scans Normal vs. Chronic Sinusitis

10. Pharynx 1. Nasopharynx Mucous-secreting Eustachian tubes Adenoids
2. Oropharynx
Digestive component
Tonsils
3. Laryngopharynx  larynx
Laryngopharynx

11. Larynx (voice box) Composed mainly of cartilage
Bound by ligaments and muscles
Contains vocal cords that stretch across from arytenoid to cricoid cartilages
Changes in tension changes pitch
Superior/anterior to larynx= epiglottis (closes off larynx during swallowing)
Anterior larynx=thyroid cartilage
(largest, contains Adam’s apple)
Inferior larynx=cricoid cartilage
Hyoid bone located here

13. Pathology of the Larynx
Vascular polyp w/ varices
Laryngocele
Leukoplakia &
underlying
carcinoma

14. LOWER RESPIRATORY TRACT
Located within the thoracic cavity
Includes the
Trachea
Bronchi
Lungs
Bronchioles
Alveolar ducts
Alveolar sacs
Alveoli

15. Trachea 4 ½ inches long, from larynx to bronchi
Held open by C-shaped cartilaginous rings
Posterior muscle
Obstruction can cause death w/in minutes
Ciliated to move
mucus out
- Smoking affects these
1 - Vocal cords 2 - Thyroid cartilage 3 - Cricoid cartilage 4 - Tracheal cartileges 5 - Balloon cuff

16. Remainder of Lower Respiratory Tract
R & L bronchi 
Contain cartilage, smooth muscle
R is wider, shorter, more vertical
Divide into secondary and tertiary bronchi 
Bronchioles (terminal and respiratory) 
Lungs (alveolar ducts and sacs)

17. Bronchi  Bronchioles  Lungs
Terminal bronchioles can dilate, constrict
Respiratory bronchioles split into
2-11 alveolar ducts each 
5-6 alveolar sacs each (look like bunches of grapes)

18. Alveolar Ducts  Alveolar Sacs  Alveoli
Alveolar sacs are microscopic and come in clusters
Made up of alveoli:
site of gas exchange b/w air and blood
Coated with surfactant (reduces surface tension, prevents them from collapsing)

19. General Structure/Location of the Lungs
Lungs: R—3 lobes, L—2 lobes (divide into lobules)
Apex: under clavicle
Base: above diaphragm
Heart in cardiac notch

20. Lobes and Lobules Functional and structural: Conducting portion
Terminal bronchioles
Clara cells – remove toxins
Type 1 alveolar cells – gas exchange
Type II alveolar cells – secrete surfactant
Surfactant – reduces surface tension of lungs, allows easier expansion; prevents collapse of alveoli
Respiratory portion
Gas exchange occurs here

21. X-Ray: Right apex tumor

22. More on Lung Structure Pleura: thin, moist, slippery (serous) membrane
Visceral pleura: covers the outer surface of the lungs
Parietal pleura: lines the inner surface of the rib cage
Produces pleural fluid-intrapleural space must remain moist
Pathology: Pleurisy (pleuritis) – painful inflammation of the pleura

23. Collapsed Lung A.k.a. = pneumothorax
Caused when atmospheric pressure enters the thoracic cavity
Normally a partial vacuum between ribcage and lungs
Trauma introduces air, which removes “suction” that keeps lungs inflated
Repaired by: chest tube