Hyperventilation or hyperpnoea causes

Options

A. Increased carbon dioxide concentration of blood
B. Decreased blood carbon dioxide concentration
C. Temporary stoppage of respiration
D. Both B and C.

Answer

**Step-by-Step Solution:**

1. **Understanding Hyperventilation and Hyperpnoea:**
- Hyperventilation refers to an increased rate and depth of breathing that leads to excessive expulsion of carbon dioxide (CO2) from the body.
- Hyperpnoea is a similar condition where there is an increase in the rate and depth of breathing, often due to increased metabolic demand.

2. **Causes of Hyperventilation:**
- Hyperventilation is often triggered by an increase in the concentration of carbon dioxide in the blood (hypercapnia). This can occur due to various factors such as physical exertion, anxiety, or respiratory disorders.

3. **Body's Response to Increased CO2:**
- When CO2 levels rise in the blood, the body responds by increasing the respiratory rate to expel more CO2. This compensatory mechanism aims to restore normal levels of CO2 and oxygen in the blood.

4. **Effects of Hyperventilation:**
- As a result of hyperventilation, there is an increased rate of breathing which leads to:
- More CO2 being expelled from the body.
- An increase in oxygen intake.
- A decrease in the concentration of carbon dioxide in the blood (hypocapnia).

5. **Conclusion:**
- Therefore, the primary effect of hyperventilation or hyperpnoea is a decrease in blood carbon dioxide concentration. This is the correct answer to the question posed.

**Final Answer:**
- Hyperventilation or hyperpnoea causes decreased blood carbon dioxide concentration.

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