Histology of the Respiratory System

Question 1

Portion of the respiratory system encompassing the following:

• nasal cavity
• pharynx
• larynx
• trachea
• bronchus
• terminal bronchiole

Answer 1

Conducting portion

Question 2

Portion of the respiratory system encompassing the following:

• respiratory bronchiole
• alveolus

Answer 2

Respiratory portion

Question 3

Airway type:

• pseudostraified columnar cell epithelium with goblet cells
• NEAR-COMPLETE circular rings or D-SHAPED structures of hyaline cartilage
• with glands
• diameter of at least 5mm

Answer 3

Primary bronchus

Question 4

Airway type:

• pseudostraified columnar cell epithelium with goblet cells
• IRREGULAR PLATE or ISLANDS of hyaline cartilage
• with glands
• diameter of at least 5mm

Answer 4

Secondary & tertiary/segmental bronchus

Question 5

Airway type:

• pseudostraified columnar cell epithelium with goblet cells
• WITHOUT cartilage or glands
• predominantly thick muscularis layer

Answer 5

Bronchiole

Question 6

Airway type:

• SIMPLE COLUMNAR cell epithelium
• without cartilage or glands

Answer 6

Terminal bronchiole

Question 7

Airway type:

• SIMPLE CUBOIDAL cell epithelium
• without cartilage or glands

Answer 7

Respiratory bronchiole

Question 8

Airway type:

• SIMPLE SQUAMOUS cell epithelium
• without cartilage or glands

Answer 8

Alveolar duct (and alveolus)

Question 9

Condition associated to increased airway resistance, due to contraction of the bronchiolar smooth muscles

Answer 9

Asthma

Question 10

Chronic lung disease characterized by enlargement of the air space DISTAL to the bronchioles with destruction of the interalveolar wall; cigarette smoking is a major cause, inducing metaplasia of the respiratory epithelium into stratified squamous epithelium

Answer 10

Ephysema

Question 11

Terminal portion of the airway; thin walled sac responsible for gas exchange

Answer 11

Alveolus (pl. alveoli)

Question 12

Alveolar cell type, simple squamous in shape, responsible for gas exchange and the lining of the blood-air barrier

Answer 12

Type I alveolar cell

Question 13

Alveolar cell type, simple cuboidal in shape, responsible for the secretion of surfactant

Answer 13

Type II alveolar cell

Question 14

Non-ciliated, microvillous, dome-shaped secretory cells found in the epithelial lining of the bronchiole, responsible for secreting surfactant-like glycosaminoglycans and divides to help regenerate epithelium

Answer 14

Clara cells (or club cells, or bronchiole exocrine cells)

Question 15

Small, scattered neuroendocrine cells that line and scatter along the basement membrane of bronchi and bronchioles responsible for releasing serotonin

Answer 15

Kultchitsky cells (or enterochromaffin/EC cells, or respiratory endocrine cells)

Question 16

Macrophages found within the alveolus, sometimes found with dark/black deposits in the setting of coal miner’s lung, pneumoconioses, or inhalation of particulate matter

Answer 16

Dust cells (or alveolar macrophages)

(Specialized macrophages:

• lung = dust cell
• liver = Kupffer or Kupffer-Browicz cell
• CNS = microglia
• bone = osteoclast
• tissue = histiocyte
• granuloma = epithelioid cell
• foreign bodies = foreign body giant cell
• granulomatous disease = Langhans giant cell
• high-lipid lesions = Touton giant cell
• Hodgkin’s lymphoma = Reed-Sternberg cell)