AIIMS2008ZoologyBreathing and Exchange of Gases
Assertion : Ciliated epithelium is present in the inner lining of trachea and large bronchi. Reason : Ciliary movement propel the mucus and foreign particle towards the larynx.
Options
- AIf both assertion and reason are true and reason is the correct explanation of assertion
- BIf both assertion and reason are true but reason is not the correct explanation of assertion
- CIf assertion is true but reason is false
- DIf both assertion and reason are false.
Correct answer
B. If both assertion and reason are true but reason is not the correct explanation of assertion
Step-by-step solution
Trachea and large bronchi are lined by pseudostratified ciliated columnar epithelium bearing glandular cells (mucous gland). The secretion of mucous glands keeps the walls of trachea and large bronchi moist and traps dust particles which enter with the air. The vibratile cilia of the epithelium then carry the mucous containing dust particles upto the larynx where they can be spitted out.