Which of the following listed respiratory centres in the brain can reduce the expiratory duration upon stimulation?

Options

A. Medullary inspiratory centre
B. Pneumotaxic centre
C. Apneustic centre
D. Chemosensitive centre

Answer

To solve the question, "Which of the following listed respiratory centres in the brain can reduce the expiratory duration upon stimulation?", we will analyze each option provided.

### Step-by-Step Solution:

1. **Understanding the Question**: We need to identify which respiratory center in the brain is responsible for reducing the duration of expiration when stimulated.

2. **Analyzing the Options**:
- **Option 1: Medullary Inspiratory Center**: This center primarily controls inspiration. It increases the rate and depth of breathing but does not reduce expiratory duration. Therefore, this option is incorrect.

- **Option 2: Pneumotaxic Center**: This center is located in the pons and plays a crucial role in regulating the rhythm of breathing. It helps to limit the duration of inspiration, which indirectly reduces the duration of expiration. This makes it the correct answer.

- **Option 3: Apneustic Center**: This center promotes prolonged inspiration and is involved in deep and prolonged breaths. It does not reduce the expiratory duration, making this option incorrect.

- **Option 4: Chemosensitive Center**: This center responds to chemical changes in the blood, such as CO2 and O2 levels. It does not directly control the duration of expiration, so this option is also incorrect.

3. **Conclusion**: After evaluating all options, the correct answer is **Option 2: Pneumotaxic Center**, as it reduces the expiratory duration upon stimulation.

### Final Answer:
**Option 2: Pneumotaxic Center**