Question

Arrange the following in the correct sequence of branching in conducting zone and respiratory zone of respiratory passage.
(A) Alveolar sacs
(B) Bronchi
(C) Bronchioles
(D) Trachea
(E) Alveolar ducts

• A. (C), (A), (E), (D), (B)
• B. (A), (D), (B), (C), (E)
• C. (B), (A), (D), (C), (E)
• D. (D), (B), (C), (E), (A)
• E.

Hint:

Always remember the branching order of respiratory system: Trachea → Bronchi → Bronchioles → Alveolar ducts → Alveolar sacs.

Answer 1

The Correct Option is D

Step 1: Starting point - Trachea.
Air enters the conducting system through the trachea, which is the largest airway tube supported by cartilaginous rings.
Hence, the first structure is (D) Trachea.
Step 2: Division into bronchi.
The trachea divides into the right and left primary bronchi, which then branch into secondary and tertiary bronchi.
Therefore, the second structure is (B) Bronchi.
Step 3: Passage into bronchioles.
Bronchi further subdivide into smaller bronchioles. These lack cartilage and are smaller airways that continue the conducting pathway.
Thus, the third structure is (C) Bronchioles.
Step 4: Transition to respiratory zone - alveolar ducts.
The bronchioles eventually branch into alveolar ducts, which directly lead to gas-exchanging areas.
Thus, the fourth structure is (E) Alveolar ducts.
Step 5: Final structures - alveolar sacs.
The alveolar ducts open into alveolar sacs, which consist of clusters of alveoli. These are the primary sites of gas exchange.
Thus, the fifth and final structure is (A) Alveolar sacs.
Step 6: Conclusion.
The correct sequence of branching is: (D) Trachea → (B) Bronchi → (C) Bronchioles → (E) Alveolar ducts → (A) Alveolar sacs.