Parathormone is secreted during

Options

A. Increased `Ca^(2+)` level in blood
B. Decreased blood `Ca^(2+)` level
C. Increased blood sugar level
D. Decreased blood sugar level.

Answer

**Step-by-Step Solution:**

1. **Understanding Parathormone**: Parathormone, also known as parathyroid hormone (PTH) or parathyrin, is a hormone secreted by the parathyroid glands. It plays a crucial role in regulating calcium levels in the blood.

2. **Function of Parathormone**: The primary function of parathormone is to control serum calcium concentration. It achieves this by acting on three main organs: the bones, kidneys, and intestines.

3. **Bone Remodeling**: Parathormone is involved in bone remodeling, a process where bone tissue is continuously reabsorbed and replaced. This process is essential for maintaining healthy bone structure and calcium levels.

4. **Trigger for Secretion**: Parathormone is secreted when there is a **decreased level of calcium** in the blood serum. This is a critical point, as the secretion of parathormone is directly linked to low calcium levels.

5. **Mechanism of Action**: Once secreted, parathormone stimulates the development of osteoclasts in the bone matrix. Osteoclasts are cells that break down bone tissue, releasing ionic calcium into the bloodstream, which helps to increase blood calcium levels.

6. **Conclusion**: Based on the information, parathormone is secreted during decreased blood calcium levels. Therefore, the correct answer to the question is that parathormone is secreted during decreased blood calcium levels.

**Final Answer**: Parathormone is secreted during decreased blood calcium levels.

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