Thyrocalcitonin is secreted during

Options

A. Increased blood calcium level
B. Decreased blood calcium level
C. Both A and B
D. Increased blood sugar level

Answer

**Step-by-Step Solution:**

1. **Understanding Thyrocalcitonin:** Thyrocalcitonin, also known simply as calcitonin, is a hormone secreted by the thyroid gland. Its primary role is to regulate calcium levels in the blood.

2. **Function of Thyrocalcitonin:** Calcitonin decreases the concentration of calcium ions in the blood. It does this by inhibiting the activity of osteoclasts (cells that break down bone) and promoting the uptake of calcium by bones.

3. **Conditions for Secretion:** Calcitonin is secreted primarily when there is an **increased blood calcium level**. This is the body's way of maintaining homeostasis, ensuring that calcium levels do not rise excessively.

4. **Analyzing the Options:**
- **Increased blood calcium level:** This is correct, as calcitonin is released to lower high calcium levels.
- **Decreased blood calcium level:** This is incorrect, as calcitonin is not secreted when calcium levels are low; instead, parathyroid hormone (PTH) is released in such cases to increase calcium levels.
- **Both A and B:** This is incorrect since calcitonin is not secreted during decreased calcium levels.
- **Increased blood sugar level:** This is also incorrect, as calcitonin does not play a role in regulating blood sugar levels.

5. **Conclusion:** Therefore, the correct answer to the question "Thyrocalcitonin is secreted during" is **increased blood calcium level**.

**Final Answer:** Increased blood calcium level.

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