Layer of columnar cells with uneven appearance and lining trachea is

Options

A. Brush border epithelium
B. Pseudostratified epithelium
C. Stratified epithelium
D. Ciliated epithelium.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question:**
The question asks about a specific type of epithelial tissue that consists of columnar cells with an uneven appearance and is found lining the trachea.

2. **Identifying Key Characteristics:**
- The term "columnar cells" refers to cells that are taller than they are wide, resembling columns.
- "Uneven appearance" suggests that the cells are arranged in a way that gives the illusion of multiple layers, even though they are actually a single layer.

3. **Analyzing the Options:**
- **Brush Border Epithelium:** This type is characterized by microvilli and is typically found in the small intestine and kidneys. It does not match the description.
- **Pseudo Stratified Epithelium:** This type appears to have multiple layers due to the varying heights of the cells, but it is actually a single layer. It is commonly ciliated and is found in the lining of the trachea and upper respiratory tract.
- **Stratified Epithelium:** This type consists of multiple layers of cells and is found in areas such as the pharynx, anus, and uterus. It does not match the description of columnar cells.
- **Ciliated Epithelium:** While this type can be ciliated, it does not specifically refer to the arrangement of the cells as being pseudo stratified.

4. **Conclusion:**
Based on the analysis, the correct answer is **pseudo stratified epithelium**, specifically ciliated pseudo stratified columnar epithelium, which lines the trachea.

**Final Answer:** Pseudo stratified epithelium.

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