Histology

Question 1

Describe how they type of epithelium lining the upper respiratory tract changes

Answer 1

• The initial part of the nasal cavity, the vestibule, is lined by keratinised stratified squamous epithelium.
• Deeper into the nasal cavity, the keratin is lost, and deeper still it changes again to the epithelium that lines nearly all of the rest of the conducting part of the respiratory system: pseudostratified ciliated columnar epithelium with goblet cells, or Respiratory Epithelium.
The laryngopharynx and oropharynx are lined by stratified squamous epithelium as they have to be resistant to abrasion as food also passes down here.

Question 2

Bronchioles are less than _____ in diameter and lack ________ and glands but may contain a few ______ in their initial portion. The main cell type present is ______

Answer 2

1mm
cartilage
goblet cells
cuboidal epithelial cells

Question 3

What are the smallest bronchioles that lack respiratory function called and what do they branch into?

Answer 3

Terminal bronchioles and they branch into respiratory bronchioles.

Question 4

Describe the two types of alveolar cell

Answer 4

1) Type 1 Alveolar Cells/ Pneumocytes

These cells provide a barrier of minimal thickness that is permeable to gases.

These are simple squamous epithelium

2) Type 2 Alveolar Cells/ Pneumocytes

Production of surfactant to break surface tension and tendency for alveoli to collapse on end of expiration

These are polygonal in shape

Question 5

Describe the lung pleura

Answer 5

• Lung is surrounded by a visceral pleura that is multi-layered.
• There is an outer layer of simple squamous epithelium called mesothelium backed by layers of fibrous and elastic connective tissue.
• This would face the parietal pleura which is a similar but generally simpler membrane lining the thoracic cavity.
• Between the two would be a pleural cavity containing a small amount of lubricating fluid.

Question 6

Describe histology of the trachea

Answer 6

Pseudo stratified ciliated columnar epithelium and goblet cells. Basal lamina. Lamina propria of connective tissue and elastic fibres. Submucosa of loose connective tissue and subserous glands. Incomplete cartilage rings.

Question 7

Histology of the larynx excluding vocal folds?

Answer 7

Pseudo stratified ciliated columnar epithelium and goblet cells covering cartilage and intrinsic muscles.

Question 8

Histology of vocal folds?

Answer 8

Stratified squamous epithelium surrounded by respiratory epithelium

Question 9

What are club/ clara cells?

Answer 9

non-ciliated cells found in terminal bronchioles. They act as immune modulators and stem cells and are able to produce surfactant.

Question 10

Difference between cartilage in bronchi and trachea

Answer 10

In the bronchi the rings of hyaline cartilage are replaced by irregularly shaped cartilage plates

Question 11

As you move down the bronchioles what happens to the epithelium?

Answer 11

Decrease in height

Question 12

What are terminal bronchioles lined with?

Answer 12

cuboidal ciliated epithelium and non-ciliated club cells.