Q149 / 180 · AIIMS 2008 · Zoology

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.

  • A
    If both assertion and reason are true and reason is the correct explanation of assertion
  • Correct answer
    B
    If both assertion and reason are true but reason is not the correct explanation of assertion
  • C
    If assertion is true but reason is false
  • D
    If both assertion and reason are false.

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.

Hence, the correct answer is option: 'B'.

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