Respiratory Airways

Question 1

Extrapulmonary Airways

Answer 1

Nasal cavities
Paranasal sinuses
Nasopharynx
Larynx
Trachea

Question 2

Intrapulmonary Airways

Answer 2

Bronchi
Bronchioles
Alveoli
Blood-air Barrier

Question 3

Nasal cavities

Answer 3

two cavities separated by the nasal septum

Question 4

Nasal mucosa

Answer 4

respiratory epithelium – lines most of the nasal cavity and other airways

respiratory lamina propria
o contains a complex vascular network, with capillary loops near the surface warming
the inspired air

olfactory epithelium – located in the roof of the nasal cavity; provides sense of smell

olfactory lamina propria
o contains olfactory glands (Bowman’s glands)

Question 5

Paranasal sinuses –

Answer 5

bilateral cavities in the frontal, maxillary, ethmoid and sphenoid bones

Question 6

Nasopharynx

Answer 6

communicates with the nasal cavities via choanae, with the tympanic cavities
(middle ear) via the pharyngotympanic tubes, and with the oropharynx
o lined by respiratory epithelium
o location of pharyngeal and tubal tonsils

Question 7

Larynx

Answer 7

link between the pharynx and trachea

2 folds: vestibular (respiratory epithelium) / vocal (stratified squamous epithelium, vocalis muscle).

Question 8

Trachea

Answer 8

lined by respiratory mucosa

Question 9

Bronchi

Answer 9

the trachea divides into two primary bronchi, one going to each lung

each primary bronchus divides into secondary or lobar bronchi: 3 for the right lung and 2 for
the left lung

as bronchi decrease in diameter, there is also progressive decrease in:
 amount of cartilage
 number of glands
 number of goblet cells
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 height of epithelial cells
o as bronchi decrease in diameter, there is a progressive increase in:
 relative amounts smooth muscle
 relative amounts of elastic tissue

Question 10

Bronchioles

Answer 10

terminal branches of bronchi

lack mucosal glands and cartilage
o epithelium transitions from pseudostratified ciliated columnar, to simple columnar, to
simple cuboidal
o contain Clara cells/club cells, which are exocrine bronchiolar cells
 secrete surfactant
 enzymes in SER detoxify inhaled xenobiotic compounds
 secrete antimicrobial peptides and cytokines
 a stem cell subpopulation undergoes mitosis to produce new cells
o contain chemosensory brush cells and DNES small granule cells
o terminal bronchioles are the smallest non-respiratory branches of bronchioles
o respiratory bronchioles have alveoli opening into their walls
o alveolar ducts are completely lined by alveoli
o alveolar sacs are at the ends of alveolar ducts and are formed of alveoli

Question 11

Alveoli

Answer 11

tiny air-filled sacs, about 200 μm in diameter
give lungs a spongy structure
surrounded by capillary networks with which O2 and CO2 are exchanged

Question 12

Blood-air barrier

Answer 12

In order for an exchange between O2 and CO2 in the alveoli, the two gasses must pass
through the blood-air barrier, which consists for the following structures:
 type I alveolar cell membranes and cytoplasm
 fused basal lamina of type I cells and endothelial cells
 endothelial cell membranes and cytoplasm
 (to these three layers we can also add the layer of surfactant that coats the inner
surface of the alveolus)