When parathyroid gland degenerates, which activity is disturbed ?

Options

A. Growth
B. Calcium concentration
C. Potassium concentration
D. Sodium concentration

Answer

### Step-by-Step Solution:

1. **Understand the Function of the Parathyroid Gland**:
The parathyroid glands are small endocrine glands located behind the thyroid gland. Their primary function is to regulate calcium levels in the blood.

2. **Identify the Hormone Secreted**:
The parathyroid glands secrete parathyroid hormone (PTH), which plays a crucial role in maintaining calcium homeostasis.

3. **Determine the Role of PTH**:
The main actions of PTH include increasing the plasma calcium concentration and decreasing the plasma phosphate concentration. It achieves this by acting on bones, kidneys, and indirectly on the gastrointestinal tract.

4. **Analyze the Effects of Degeneration**:
If the parathyroid gland degenerates, the secretion of PTH will be reduced or halted. This will disrupt the regulation of calcium levels in the blood.

5. **Evaluate the Options Given**:
The question provides four options: growth, calcium concentration, potassium concentration, and sodium concentration. Since the primary role of PTH is to regulate calcium levels, the most affected activity when the parathyroid gland degenerates will be calcium concentration.

6. **Conclusion**:
Therefore, when the parathyroid gland degenerates, the activity that is disturbed is the calcium concentration.

### Final Answer:
**Calcium concentration is disturbed when the parathyroid gland degenerates.**

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