Histology

Question 1

What are the histological layers of the upper respiratory tract?

Answer 1

The epithelium

Lamina propria All three are called the mucosa

Muscularis mucosa

Sub mucosa - cartilage in trachea (CT)

Adventitia - CT layer.

Question 2

Brief description of the distinctive histological make-up of the trachea?

And the difference in the primary bronchi?

And then the secondary/tertiary bronchi?

The Bronchioles?

Answer 2

Trachea:

• C - shaped cartilage
• Trachealis muscle on the posterior wall

Primary Bronchi:

• Plates of cartilage
• No trachealis muscle

Secondary/tertiary Bronchi:

• Cartilage plates present but less frequent
• Likely to be surrounded by alveoli

Bronchioles:

• Smooth muscle layer
• No cartilage, no glands.

Question 3

The type of epithelia in the bronchioles?

Answer 3

Ciliated simple columnar changing slowly to simple cuboidal.

Question 4

What do the respiratory and terminal bronchioles supply?

Answer 4

A respiratory bronchiole supplies an acinus, a terminal bronchiole supplies a pulmonary lobule.

SO Terminal bronchiole BEFORE a respiratory bronchiole.

Question 5

Three main types of cells in an alveoli?

Answer 5

Type I and II pneumocytes

Alveolar macrophages