The upper respiratory system consists of the nasal cavity, pharynx, and larynx. The nasal cavity functions to warm and humidify inhaled air before it reaches the lungs. It contains hairs and mucus that filter out dust and pathogens. The pharynx is divided into the nasopharynx behind the nasal cavity and the oropharynx behind the mouth. The larynx contains vocal cords and cartilage that act to keep the airway open while also allowing for speech and swallowing.

2. Nose – air enters and leave, hairs block entry of dust

3. Nasal mucous – ciliated epithelium, with goblet cells that product mucous

4. Conchae – increases surface area of the nasal mucosa

5. Olfactory receptors – detect vaporized chemicals that have been inhaled, the olfactory nerves pass through the ethmoid bone to brain

6. Paranasal sinuses – air cavities in the maxillae, frontal, sphenoid and ethmoid bones. Bones are lined with cilia epithelium, mucous produced drains into cavity. Provide resonance for the voice (more air).

7. Nasal cavities warm air and humidity to 100% prior to reaching lungs

8. Pharynx

9. Nasopharynx– behind nasal cavities

10. Soft palate - elevated during swallowing to block nasopharynx and prevent food or saliva from going up rather than down

11. Eustachian tubes – permit air to enter or leave middle ears, allowing ear drums to vibrate properly

12. Oropharynx– behind mouth, its mucosa is stratified squamous epithelium.

13. Lymph nodules, adenoid and lingual tonsils form ring of lymphatic tissue around pharynx to destroy pathogens.

14. Larynx

15. Passageway for air between the pharynx and the trachea

16. Mucosa layer is called ciliated epithelium (except the vocal cords) they sweep upward to remove mucous, trapped dust and microorganisms

17. Made of nine pieces of cartilage connected by ligaments to keep airway open at all times

18. Thyroid cartilage – largest cartilage

19. Epiglottis – uppermost cartilage, acts as trap door when swallowing to prevent entry of saliva or food into larynx

20. Vocal cords – on either side of glottis. During breathing the VC are held at the sides of glottis to that air passes freely in and out of trachea