Which statement is wrong ?

Options

A. The partial pressure of `CO_(2)(pCO_(2))` is higher in the air inside the lungs than inside the venous blood
B. The partial pressure of `O_(2)(pO_(2))` is higher inside the venous blood than in the air in the lung
C. The partial pressure of `O_(2)(pO_(2))` is lower inside the venous blood than in the air in the lung
D. The partial pressure of `CO_(2)(pCO_(2))` is higher inside the venous blood than in the air .

Answer

To determine which statement is wrong regarding the exchange of gases in the respiratory system, we will analyze the statements provided about the partial pressures of carbon dioxide (CO2) and oxygen (O2) in the lungs and blood.

### Step-by-Step Solution:

1. **Understand the Concept of Partial Pressure**:
- Partial pressure refers to the pressure exerted by a single type of gas in a mixture of gases. It is a crucial concept in understanding gas exchange in the lungs.

2. **Analyze the First Statement**:
- The first statement claims that the partial pressure of CO2 in the lungs (alveolar air) is more than in venous blood.
- In reality, the partial pressure of CO2 in the alveolar air is approximately 40 mmHg, while in venous blood, it is about 45 mmHg.
- **Conclusion**: This statement is incorrect because CO2 is higher in venous blood than in alveolar air.

3. **Analyze the Second Statement**:
- The second statement asserts that the partial pressure of O2 is more in venous blood than in alveolar air.
- The partial pressure of O2 in venous blood is approximately 40 mmHg, whereas in alveolar air, it is around 104 mmHg.
- **Conclusion**: This statement is also incorrect because O2 is higher in alveolar air than in venous blood.

4. **Analyze the Third Statement**:
- The third statement indicates that the partial pressure of O2 is lower in venous blood than in alveolar air.
- As established, venous blood has about 40 mmHg of O2 while alveolar air has about 104 mmHg.
- **Conclusion**: This statement is correct.

5. **Analyze the Fourth Statement**:
- The fourth statement mentions that the partial pressure of CO2 is higher in blood than in alveolar air.
- Since venous blood has a CO2 concentration of about 45 mmHg and alveolar air has about 40 mmHg, this statement is accurate.
- **Conclusion**: This statement is correct.

6. **Identify the Wrong Statements**:
- The first and second statements are wrong based on the analysis of partial pressures.
- Therefore, the answer to the question is that the wrong statements are the first and second.

### Final Answer:
The wrong statements are:
- Statement 1: "Partial pressure of CO2 in lungs is more in alveolar air and less in venous blood."
- Statement 2: "Partial pressure of O2 is more in venous blood and less in alveolar air."