Which one of the following is the incorrect statement for respiration in humans ?

Options

A. Cigarette smoking may lead to inflammation of bronchi.
B. Neural signals from pneumotaxic centre in pons region of brain can increase the respiratory rate.
C. Workers in grinding and stone-breaking industries may suffer from lung fibrosis.
D. None of these

Answer

To determine which statement about respiration in humans is incorrect, we will analyze each option provided:

1. **Cigarette smoking may lead to the inflammation of bronchi.**
- Cigarette smoking is known to cause various respiratory problems, including inflammation of the bronchi, which can lead to chronic bronchitis and other disorders. This statement is **correct**.

2. **Neural signals from the pneumotoxic center in the pons region of the brain can increase the respiratory rate.**
- The pneumotoxic center in the pons does play a role in regulating the respiratory rhythm. However, its primary function is to moderate and potentially decrease the inspiratory phase, which can lead to a decrease in the respiratory rate rather than an increase. Therefore, this statement is **incorrect**.

3. **Workers in the grinding and stone breaking industries may suffer from lung fibrosis.**
- Workers in these industries are indeed at risk for lung fibrosis due to inhalation of silica dust and other pollutants. This statement is **correct**.

4. **None of these.**
- This option suggests that all previous statements are correct. However, since we identified the second statement as incorrect, this option cannot be true.

Based on the analysis, the **incorrect statement** regarding respiration in humans is the second option: "Neural signals from the pneumotoxic center in the pons region of the brain can increase the respiratory rate."

### Summary of the Solution:
- The first statement is correct (cigarette smoking causes inflammation).
- The second statement is incorrect (the pneumotoxic center decreases respiratory rate).
- The third statement is correct (lung fibrosis in certain workers).
- The fourth option is incorrect because not all statements are correct.

### Final Answer:
The incorrect statement for respiration in humans is: **Neural signals from the pneumotoxic center in the pons region of the brain can increase the respiratory rate.**

---