Question

Cartilaginous rings are not present in______

• A. Primary Bronchi
• B. Terminal Bronchioles
• C. Secondary Bronchi
• D. Trachea

Answer 1

The correct option is (B):

Explanation of the correct option:

1. The cartilaginous rings are present mainly towards the upper part of the respiratory tract.
2. The terminal bronchiole does not possess the cartilaginous rings that are required to stop the tract from collapsing during exhaling.
   
3. They have elastic fibres associated with the lung tissue to support the structure.
   

Explanation of the incorrect options:

Option (A):

1. Primary bronchiole is the first branch that originates from the bronchus. ​
2. It contains the hyaline cartilage to support its structure.
   

Option (C):

1. ​Trachea is called the windpipe of the respiratory tract.
   
2. The continuous C-shaped hyaline cartilages are present to stop the structure from collapsing.
   

Option (D):

1. The secondary bronchi is also present ​towards the middle of the lungs where it possesses hyaline cartilage.
   

Final Answer: Cartilaginous rings are not present in terminal bronchi.