Cell Bio of the Lungs

Question 0

What is the cartilage like in the bronchi?

Answer 0

Irregular plates (in contrast to the C-shaped rings of the trachea)

Question 1

How does the epithelium of the bronchioles differ from that of the trachea and bronchi? (2 things)

Answer 1

Bronchioles have simple cuboidal epithelium (vs. pseuodostratified ciliated).
Bronchioles have Clara cells instead of goblet cells.

Question 2

Do the bronchioles have glands?

Answer 2

Nope.

Question 3

Which level of the bronchial tree has the greatest proportion of smooth muscle?

Answer 3

the bronchioles have the most smooth muscle.

Question 4

What are the cells in pseudostratified ciliated columnar epithelium that don’t reach the lumen?
What is their function?

Answer 4

Basal cells -these are stem cells for renewal of the epithelium.

Question 5

Mucociliary transport involves 2 layers.

Answer 5

Yeah, the mucous layer and the watery layer.

The watery layer is where the cilia beat.

Question 6

Which cells transport Cl- into the lumen?

What does this accomplish?

Answer 6

The ciliated epithelial cells move Cl- into the lumen.

Question 7

What molecule confers motility to cilia?

What happens if this molecule is defective?

Answer 7

Dynein - a motor protein.

If defective, Kartagener’s syndrome: male infertility (sperm immobile), chronic bronchitis, hearing problems.

Question 9

2 cell types in the pseudostratified ciliated columnar (PCC) epithelium other than ciliated (30%) and goblet cells (30%)?
Function?

Answer 9

Basal cells (30%) - stem cells.
Neuroendocrine aka. Kulchitsky cells (10%) - secrete peptides... affect smooth muscle tone.

Question 10

What’s the largest (most proximal) air duct that defines a pulmonary lobule?

Answer 10

A terminal bronchiole.

Respiratory bronchioles, alveolar ducts, and alveoli branch off distally.

Question 11

If you looked at the luminal wall of a terminal bronchiole, what cell type would you see the most of?

Answer 11

Clara cells.

ciliated cells are much less common

Question 12

Function of Clara cells?

Answer 12

Surfactant production.

Cytochrome P-450 to metabolize airborne toxins.

Question 13

What types of epithelial cells are in the alveoli?

Function?

Answer 13

Type I: Extremely thin, for gas exchange.
Type II: Surfactant production, stem cells.

Brush cells - monitor air quality?

Question 14

What are Pores of Kohn?

Answer 14

Connections between adjacent alveoli.

Question 15

What are some functions of alveolar macrophages?

Answer 15

Clean surfactant layer - removing dust and pollen.
Removing degraded surfactant.
Immune response - attracting PMNs.