Insulin is secreted by

Options

A. `alpha`-cell of islets of Langerhans
B. `beta`-cell of islets of Langerhans
C. `delta`-cell of islets of Langerhan
D. Pancreatic acinar cell

Answer

**Step-by-Step Solution:**

1. **Understanding the Pancreas**: The pancreas is an organ that has both endocrine and exocrine functions. It plays a crucial role in regulating blood sugar levels through the secretion of hormones.

2. **Identifying the Islets of Langerhans**: Within the pancreas, there are clusters of cells known as the Islets of Langerhans. These islets contain different types of cells, each responsible for producing specific hormones.

3. **Types of Cells in the Islets of Langerhans**:
- **Alpha Cells**: These cells secrete glucagon, which increases blood sugar levels.
- **Beta Cells**: These cells are responsible for secreting insulin, which lowers blood sugar levels.
- **Delta Cells**: These cells secrete somatostatin, which inhibits the secretion of other hormones.

4. **Exocrine Function of the Pancreas**: Apart from the islets, the pancreas also has exocrine cells (pancreatic acinar cells) that secrete digestive enzymes, but these are not involved in hormone secretion.

5. **Conclusion**: Based on the functions of the different cells in the Islets of Langerhans, insulin is specifically secreted by the **beta cells**.

**Final Answer**: Insulin is secreted by **beta cells of the Islets of Langerhans**.

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