Which statement is wrong ?

Options

A. Partial pressure of `CO_2(PCO_2)` is higher in the air inside the lungs
B. Partial pressure of `O_2(PC_2)` is higher in the air inside the lungs
C. Partial pressure of `O_2(PC_2)` is lower inside the venous blood than in the air in the lung
D. Partial pressure of `CO_2(PCO_2)` is higher inside the venous blood than in the air

Answer

To solve the question "Which statement is wrong?" regarding the partial pressures of gases, we will analyze each option based on the information provided in the video transcript.

### Step-by-Step Solution:

1. **Understanding Partial Pressure**:
- Partial pressure refers to the pressure exerted by an individual gas in a mixture of gases. It is crucial for understanding gas exchange in the lungs and tissues.

2. **Analyzing the Gaseous Exchange**:
- Gaseous exchange occurs at two levels: pulmonary (in the alveoli) and systemic (at the tissue level).
- In the alveoli, oxygen (O2) is absorbed into the blood, and carbon dioxide (CO2) is released.

3. **Partial Pressures in Different Locations**:
- **In the Alveoli**:
- Partial pressure of O2 (PO2) = 104 mmHg
- Partial pressure of CO2 (PCO2) = 40 mmHg
- **In the Systemic Artery**:
- PO2 = 95 mmHg
- PCO2 = 40 mmHg
- **In the Systemic Vein**:
- PO2 = 40 mmHg
- PCO2 = 45 mmHg

4. **Evaluating Each Statement**:
- **Statement 1**: "Partial pressure of CO2 is higher in air than inside the lung."
- This is incorrect. The partial pressure of CO2 in atmospheric air is approximately 0.3 mmHg, which is much lower than the 40 mmHg in the alveoli.
- **Statement 2**: "Partial pressure of O2 is higher in air than inside the lung."
- This is correct. The partial pressure of O2 in atmospheric air is about 159 mmHg, which is higher than 104 mmHg in the alveoli.
- **Statement 3**: "Partial pressure of O2 is lower inside the venous blood than in the air of the lung."
- This is correct. PO2 in venous blood is 40 mmHg, which is lower than 104 mmHg in the alveoli.
- **Statement 4**: "Partial pressure of CO2 is higher inside the venous blood than in the air."
- This is correct. The partial pressure of CO2 in venous blood is 45 mmHg, which is higher than 0.3 mmHg in the air.

5. **Conclusion**:
- The only incorrect statement is **Statement 1**: "Partial pressure of CO2 is higher in air than inside the lung."

### Final Answer:
**The wrong statement is Statement 1.**