Question

Identify the incorrect statement regarding respiratory system in man.

• A. Lungs are covered by double-layered membrane called pleura.
• B. The alveoli are surrounded by rich blood capillaries.
• C. The trachea, bronchi and bronchioles are supported by 'O' shaped cartilaginous rings.
• D. The right lung is slightly larger than the left lung.

Hint:

The cartilaginous rings are "incomplete" or "C-shaped" dorsally. This is a common trap in structural biology questions.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept: The human respiratory system has specific anatomical structures adapted to facilitate breathing, gas exchange, and airway protection.
Step 2: Key Formula or Approach: Evaluate each statement against the standard anatomical facts of the human respiratory system to find the conceptually flawed one.
Step 3: Detailed Explanation: Statement (1) is correct: Lungs are enclosed in a double-layered pleural membrane with pleural fluid between them to reduce friction.
Statement (2) is correct: Alveoli are the primary sites of gas exchange and are thus highly vascularized with a rich network of blood capillaries.
Statement (4) is correct: The right lung has three lobes and is slightly larger than the left lung, which has only two lobes to accommodate the cardiac notch (heart).
Statement (3) is incorrect: The trachea, primary, secondary, tertiary bronchi, and initial bronchioles are supported by incomplete 'C' shaped cartilaginous rings, not complete 'O' shaped rings.
These rings are incomplete dorsally to allow the esophagus to expand during swallowing.
Step 4: Final Answer: The incorrect statement is (3).