the structure of the upper airway

Question 1

the nose

Answer 1

Most superior portion of the respiratory tract
Multiple functions:
• Temperature of inspired air (0.25 second contact)
• Humidity (75-80% RH)
• Filter function
• Defence function – cilia take inhaled particles backwards to be swallowed
Anterior nares open into the enlarged: vestibule – skin lined, stiff hairs
Surface area of nose is doubled by turbinates

Question 2

turbinates create

Answer 2

• Superior meatus (1st gap between terbinates)– olfactory epithelium, cribriform plate, sphenoid sinus
• Middle meatus – sinus openings
• Inferior meatus – nasolacrimal duct

Question 3

The paranasal sinuses

Answer 3

Pneumatised areas of the; 
•	Frontal 
•	Maxillary 
•	Ethmoid 
•	Sphenoid bones 
Arranged in pairs 
Evagination of mucous membrane from the nasal cavity

Question 4

frontal sinuses

Answer 4

• Within frontal bone
• Midline septum
• Over orbit and across superciliary arch
• Nerve supply – ophthalmic division of V nerve

Question 5

maxillary sinuses

Answer 5

• Located within the body of the maxilla
• Pyramidal shape
• Base – lateral wall of the nose
• Apex – zygomatic process of the maxilla
• Roof – floor of the orbit
• Floor – alveolar process
• Open into the middle meatus
• Hiatus semilunaris

Question 6

Ethmoid sinuses

Answer 6

• Between the eyes
• Labyrinth of air cells
• Semilunar hiatus of the middle meatus
• Nerve supply – ophthalmic and maxillary V nerve

Question 7

Sphenoid sinuses

Answer 7

• Medial to the cavernous sinus
• Carotid artery, III, IV, V, VI
• Inferior to optic canal, dura and pituitary gland
• Empties into sphenoethmoidal recess, lateral to the attachment of the nasal septum
• Nerve supply – ophthalmic V

Question 8

Pharynx

Answer 8

• Fibromuscular tube lined with epithelium
• Squamous and columnar ciliated, mucous glands
• Skull base → C6 → Oesophagus
• Anterior → nasal cavities, mouth and larynx (nasopharynx, oropharynx, laryngopharynx (hypopharynx))

Question 9

Nasopharynx

Answer 9

bounded by:
•	Base of skull
•	Sphenoid rostrum 
•	C spine 
•	Posterior nose (choana)
•	Inferiorly at soft plate opens to oropharynx 
Eustachian tube orifices (lateral wall) – supply air to middle ear 
Pharyngeal tonsils on posterior wall

Question 10

Oropharynx

Answer 10

• Soft plate anteriorly
• Palatine tonsils on the lateral walls (palatoglossal folds, palatopharyngeal folds)
• Inferiorly to the hyoid bone

Question 11

Larynx

Answer 11

• Valvular function – prevents liquids and food from entering lung
• Rigid structure
• 9 cartilages
• Multiple muscles
• Arytenoid cartilages rotate on the cricoid cartilage to change vocal cords

Question 12

Laryngeal cartilages

Answer 12

Single: epiglottis, thyroid, cricoid
Double: cuneiform, corniculate, arytenoid

Question 13

Laryngeal innervation

Answer 13

The vagus (x) – superior laryngeal nerve, recurrent laryngeal nerve
Superior laryngeal nerve – inferior ganglion, lateral pharyngeal wall, divides into: internal (sensation) and external (cricothyroid muscle)
Recurrent laryngeal nerve – all muscles except cricothyroid
• R and L different
• Left – lateral to arch of aorta, loops under aorta, ascends between trachea and oesophagus
• Right – R subclavian artery, plane between trachea and oesophagus