HIST of the Respiratory System - Week 1

Question 1

Compare & contrast HIST of bronchus vs bronchioles.

Answer 1

Bronchioles are smaller, without cartilage, whereas bronchus have cartilage.

Question 2

What type of glands are seromucous glands - endo or exo?

Answer 2

Exocrine.

Question 3

What is the role of Club cells/Clara cells/Bronchiolar exocrine cells?

Answer 3

Secretory role @ level of terminal bronchioles.

Question 4

What is the function of lamellar bodies?

Answer 4

Store surfactant.

Question 5

Function of alveolar macrophages

Answer 5

Provide the first line of phagocytic defence against microbial invasion in the LRT.
Macrophages ‘hoover’ up used surfactant, particulate matter to ensure clean air-blood barrier.

Question 6

Describe transition btw terminal bronchioles and respiratory bronchioles.

Answer 6

Terminal bronchioles are the end of the conducting zone start to lose/decrease no. of goblet cells. Transition from ciliated pseudostratified epithelium -> simple columnar epithelium. Some cells still have cilia, but mostly not – as if there is no mucous, then no reason to have cilia.
Transition from simple columnar -> simple cuboidal until at crossover to respiratory bronchioles (start of respiratory zone) -> simple squamous to ensure gas particles are crossing shortest distance possible and increase/enable maximal gas exchange.