Ciliated epithelium lining the trachea and bronchi is advantageous because

Options

A. Cilia act as sensory hairs
B. Cilia increase the surface area of absorption
C. Cilia kill foreign microbes
D. Ciliary movement propels the mucus and foreign particle towards the larynx

Answer

**Step-by-Step Solution:**

1. **Understanding Ciliated Epithelium**: The trachea and bronchi are lined with ciliated pseudostratified columnar epithelium. This type of epithelium has cilia, which are tiny hair-like structures on the surface of the cells.

2. **Function of Cilia**: The primary function of cilia in the respiratory tract is to move mucus and trapped foreign particles upwards towards the larynx. This movement helps to clear the airways of debris and pathogens.

3. **Role in Protection**: By propelling mucus and foreign particles out of the trachea and bronchi, cilia play a crucial role in protecting the lungs from potential infections and irritants that could enter through inhaled air.

4. **Elimination of Incorrect Options**:
- **Cilia as Sensory Cells**: This is incorrect; cilia do not function as sensory cells.
- **Cilia Increasing Surface Area for Absorption**: This is also incorrect; the respiratory system does not primarily absorb substances; it is involved in gas exchange.
- **Cilia Killing Foreign Microbes**: This is not accurate; while cilia help in trapping particles, it is the immune cells that are responsible for killing microbes.

5. **Conclusion**: The correct advantage of the ciliated epithelium lining the trachea and bronchi is that the ciliary movement propels mucus and foreign particles towards the larynx, thereby keeping the respiratory tract clear and protecting the lungs.

**Final Answer**: The ciliated epithelium lining the trachea and bronchi is advantageous because ciliary movement propels the mucus and foreign particles towards the larynx.

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