Which of the structure is not associated with the mucosa layer of the small intestine?

Options

A. Villi and microvilli
B. Crypts of Leiberkuhn
C. Chief cells
D. Intestinal gland

Answer

To solve the question "Which of the structures is not associated with the mucosa layer of the small intestine?", we will analyze each of the provided options step by step.

### Step 1: Understand the Mucosa Layer
The mucosa layer of the small intestine is the innermost layer that is involved in absorption and secretion. It contains various structures that aid in these functions.

### Step 2: Evaluate the Options
1. **Villi and Microvilli**:
- These are finger-like projections that increase the surface area for absorption. They are indeed associated with the mucosal layer of the small intestine.
- **Conclusion**: This option is associated with the mucosa.

2. **Crypts of Lieberkühn**:
- These are glandular structures located in the mucosa of the small intestine. They are involved in the secretion of intestinal juices and play a role in host defense.
- **Conclusion**: This option is associated with the mucosa.

3. **Chief Cells**:
- Chief cells are primarily found in the stomach, where they secrete pepsinogen and chymosin. They are not found in the small intestine.
- **Conclusion**: This option is NOT associated with the mucosa of the small intestine.

4. **Intestinal Glands**:
- These are also known as Crypts of Lieberkühn and are located in the mucosa layer of the small intestine. They are involved in secretion.
- **Conclusion**: This option is associated with the mucosa.

### Step 3: Identify the Correct Answer
After evaluating all the options, we find that the structure that is NOT associated with the mucosa layer of the small intestine is **Chief Cells**.

### Final Answer
The correct answer is **Chief Cells**.

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