Question

The condition of a collapsed lung or atelectasis, can result from an accumulation of which substance in the pleural cavity ?

• A. Blood and fluid
• B. Surfactant
• C. Air or fluid
• D. Pus or mucus

Hint:

Atelectasis = Lung collapse → Often due to air (pneumothorax) or fluid (effusion) in pleural space.

Answer 1

The Correct Option is C

Concept: Atelectasis refers to the collapse of part or all of a lung due to loss of air in the alveoli. It can occur when the pleural cavity is filled with substances that interfere with normal lung expansion.

Step 1: Understanding pleural cavity.
The pleural cavity is the space between the lungs and chest wall. It normally contains a small amount of lubricating fluid to allow smooth movement of lungs during breathing.

Step 2: Causes of lung collapse.
Atelectasis can occur when substances accumulate in this cavity, such as:
• Air (pneumothorax)
• Fluid (pleural effusion) These substances exert pressure on the lungs, preventing them from expanding.

Step 3: Evaluating options.

• Blood and fluid – Possible but not the most general answer.
• Surfactant – Helps keep alveoli open, not causes collapse.
• Air or fluid – Correct, primary causes of atelectasis.
• Pus or mucus – Associated with infection but not general cause.

Step 4: Final evaluation.
The most appropriate and general answer is accumulation of air or fluid. Final Conclusion:
Hence, the correct answer is option (3).