L4 Histology Of Tracheopulmonary Tree

Question 1

How the tracheal rings are attached to each other ?

Answer 1

By elastic CT

Question 2

What are the contents of lamina propria ?

Answer 2

1. Serous and mucous glands
2. Spirally arranged muscles
3. Elastic fibers

Question 3

What are the cells of respiratory epithelium?

Answer 3

1. Ciliated columnar
2. Brush cells ( act as chemoreceptors )
3. Basal cells
4. Small granular cells (DNES)
5. Goblet cells

Question 4

What are the basal bodies ?

Answer 4

serve as the source of, and anchoring sites for, the ciliary axonemes

Question 5

What is BALT ?

Answer 5

It is a component of MALT, which contain B lymphocytes that will produce IgA which is wet membrane immunoglobulins

Question 6

What are the trends of the components as you are going down ?

Answer 6

Muscles + elastic fibers + BALT ( increase )

Cartilages + CT ( decreases )

Question 7

What is the structure of terminal bronchioles?

Answer 7

LARGE :

• no cartilage
• no glands
• psuedostratified columnar ciliated cells with goblet cells

Small :

• no cartilage
• no glands
• simple columnar or cuboidal without goblet cells
• clara cells

Question 8

What are clara cells ? What are there function ?

Answer 8

Clara cells in the epithelium of a terminal bronchiole.
These cells show secretory granules and a bulging apical cytoplasm, no cilia.

Function of the secretion: protection of the bronchiole lining (antimicrobial,Detoxification, secretion of surfactant, stem cell

Question 9

What is the structure of respiratory bronchioles?

Answer 9

• no cartilage
• no glands
• simple columnar or cuboidal ciliated without goblet cells ( being non ciliated at the end )
• clara cells
• alveoli start to open ( the main difference )

Question 10

What is the type of epithelium in alveolar ducts and alveoli ?

Answer 10

Both the alveolar ducts and the alveoli themselves are lined with extremely attenuated squamous cells’

Question 11

What is interalveolar septum? And what is its components ?

Answer 11

Consists of 2 thin squamous epithelial

layers between them interstitium of connective tissue (C.T.), and capillaries.

Function of elastic and reticular fibers

Question 12

What does the air-blood barrier (respiratory membrane ) is made of ?

Answer 12

1. Surfactant ( surface lining )
2. Sequamous epithelium
3. Fused basal lamina
4. Non-fenestrated endothelium

Question 13

What are special structures for pnumocyte II ?

Answer 13

1. Microvilli

2. Junctional complexes

Question 14

What is the importance of Alveolar pores ?

Answer 14

equalize air pressure in alveoli

And promote the collateral circulation of air when a bronchiole is obstructed.