Cells of the pancreas are not digested by their own enzymes because

Options

A. Enzymes are secreted in inactive form
B. Cells are lined by mucous membrane
C. Enzymes are released only when needed
D. None of the above

Answer

To answer the question "Cells of the pancreas are not digested by their own enzymes because", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Pancreatic Enzymes**: The pancreas produces several digestive enzymes, including proteolytic enzymes that break down proteins. These enzymes are essential for digestion.

2. **Inactive Form of Enzymes**: The key reason that pancreatic cells are not digested by their own enzymes is that these enzymes are secreted in an inactive form, known as proenzymes or zymogens. For example, pepsinogen is the inactive form of pepsin, and trypsinogen is the inactive form of trypsin.

3. **Activation in the Intestine**: Once these proenzymes reach the intestine, they are activated into their active forms. This activation occurs in a controlled environment, which prevents the enzymes from digesting the pancreatic cells themselves.

4. **Protection Mechanism**: By secreting enzymes in an inactive form, the pancreas protects itself from autodigestion. If the enzymes were active while still in the pancreas, they would start digesting the pancreatic tissue.

5. **Eliminating Other Options**:
- The option stating that "cells are lined by mucous membrane" is incorrect because while mucus does provide some protection, it is not the primary reason for preventing autodigestion.
- The option stating "enzymes are released only when needed" is also misleading, as the enzymes are always produced but remain inactive until they reach the intestine.
- The option "none of the above" is incorrect since we have identified a valid reason.

6. **Conclusion**: Therefore, the correct answer to the question is that pancreatic cells are not digested by their own enzymes because **enzymes are secreted in inactive form**.

### Final Answer:
**Option A: Enzymes are secreted in inactive form.**

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