Mark antagonistic hormones

Options

A. Insulin and glucagon
B. Adrenaline and nor adrenaline
C. Calcitonin and parathormone
D. Both (1) & (3)

Answer

To mark antagonistic hormones, we need to identify pairs of hormones that have opposite actions in the body. Let's analyze the given options step by step.

### Step-by-Step Solution:

1. **Understanding Antagonistic Hormones**:
- Antagonistic hormones are those that have opposing effects on the same physiological function.

2. **Analyzing Option 1: Insulin and Glucagon**:
- **Insulin**: Produced by the pancreas, it lowers blood glucose levels by facilitating the uptake of glucose into cells.
- **Glucagon**: Also produced by the pancreas, it raises blood glucose levels by stimulating the liver to release glucose.
- **Conclusion**: Since insulin decreases blood glucose and glucagon increases it, they are antagonistic hormones.

3. **Analyzing Option 2: Adrenaline and Noradrenaline**:
- **Adrenaline**: Secreted from the adrenal medulla, it prepares the body for 'fight or flight' responses.
- **Noradrenaline**: Also secreted from the adrenal medulla, it works alongside adrenaline in stress responses.
- **Conclusion**: Both hormones work together and do not have opposing actions, hence they are not antagonistic.

4. **Analyzing Option 3: Calcitonin and Parathormone**:
- **Calcitonin**: Secreted by the thyroid gland, it lowers blood calcium levels.
- **Parathormone (PTH)**: Secreted by the parathyroid glands, it raises blood calcium levels.
- **Conclusion**: Since calcitonin decreases calcium levels and parathormone increases them, they are antagonistic hormones.

5. **Final Conclusion**:
- From the analysis, we find that:
- **Option 1 (Insulin and Glucagon)**: Antagonistic
- **Option 2 (Adrenaline and Noradrenaline)**: Not antagonistic
- **Option 3 (Calcitonin and Parathormone)**: Antagonistic
- Therefore, the correct answer is **Option 4: Both 1 and 3** are pairs of antagonistic hormones.

### Final Answer:
**Option 4: Both 1 and 3 (Insulin and Glucagon; Calcitonin and Parathormone) are antagonistic hormones.**