What is the function of the goblet cells in the gas exchange system?
▶️ Answer/Explanation
Ans: C
Goblet cells secrete mucus, which traps dust and pathogens (D is incorrect as it describes the function of mucus, not goblet cells). Cilia (B) move mucus, and surface area is increased by structures like microvilli (A). Thus, the correct answer is C (to release mucus).
The photomicrograph shows a section through part of the gas exchange system.
Which tissue can be seen?
▶️ Answer/Explanation
Ans: D
The question references a photomicrograph (not shown) of gas exchange tissue. Squamous epithelium (D) forms the alveoli walls where gas exchange occurs. Ciliated epithelium (B) is in airways, cartilage (A) supports larger airways, and smooth muscle (C) controls airway diameter but isn’t directly involved in gas exchange.
Which structures are present in the trachea and also in all bronchioles?
- cartilage
- smooth muscle
- epithelial cells
▶️ Answer/Explanation
Ans: C
All airways have epithelial cells (3) and smooth muscle (2) for protection and diameter regulation. Cartilage (1) is only in trachea and bronchi – absent in bronchioles. Thus, the correct combination present in both is smooth muscle and epithelial cells (option C).
Which row is correct for the wall of the trachea and the wall of the bronchus?
▶️ Answer/Explanation
Ans: A
Both trachea and bronchi contain cartilage rings (support), smooth muscle (airway diameter control), and goblet cells (mucus production). The only difference is that bronchi have irregular cartilage plates instead of complete rings. Therefore, all three components are present in both structures.