Question

Which one of the following epithelial cell types is primarily located in the tracheal mucosa of a healthy adult human?

• A. Transitional
• B. Keratinized stratified squamous
• C. Simple squamous
• D. Ciliated pseudostratified columnar

Hint:

Think about what the trachea must do every second: sweep mucus and trapped dust upward. That needs cilia.

Answer 1

The Correct Option is D

The question is about matching an epithelial tissue type to its job in the airway. The trachea has to sweep mucus and trapped debris upward all the time, so its lining must be built for that.

1. Transitional: found in the urinary tract, where the tissue needs to stretch and recoil as the bladder fills and empties. It plays no role in moving mucus.
2. Keratinized stratified squamous: found in the skin, built as a tough, dry, multi layered barrier against wear. It has no cilia and cannot move mucus.
3. Simple squamous: a single layer of flat cells lining the alveoli and blood vessels, chosen because it is so thin that gases or small molecules cross quickly. It is too fragile and has no cilia for the tracheas job.
4. Ciliated pseudostratified columnar: this is the correct fit. It carries motile cilia on top and goblet cells that make mucus, so together they trap particles and sweep them up and out of the airway, a process called mucociliary clearance.

Because the trachea needs both mucus production and a way to physically move that mucus, only ciliated pseudostratified columnar epithelium fits, making option (D) correct.

Let's summarize:

• Epithelial type follows function: stretch needs transitional, wear resistance needs keratinized squamous, fast exchange needs simple squamous.
• Mucus clearance in the airway needs cilia plus goblet cells, found only in ciliated pseudostratified columnar epithelium.

The tracheal mucosa is lined by ciliated pseudostratified columnar epithelium.