Read the statements below and identify the one that will not help in increasing the efficiency of gaseous exchange in the alveoli .

Options

A. The blood capillaries and alveoli have a large total surface area.
B. The blood flow is slowed as it passes through the pulmonary capillaries .
C. The thickness of the respiratory membrane is increased
D. The walls of the alveoli and capillaries are very thin

Answer

To solve the question, we need to analyze each statement provided and determine which one does not contribute to increasing the efficiency of gaseous exchange in the alveoli.

### Step-by-Step Solution:

1. **Understanding Gaseous Exchange**: Gaseous exchange occurs in the alveoli of the lungs where oxygen is absorbed into the blood, and carbon dioxide is released from the blood into the alveoli. The efficiency of this process can be influenced by several factors.

2. **Evaluating the First Statement**: "Blood capillaries and alveoli have a large total surface area."
- **Analysis**: A larger surface area allows for more space for gas exchange to occur, which increases efficiency.
- **Conclusion**: This statement helps in increasing the efficiency of gaseous exchange.

3. **Evaluating the Second Statement**: "The blood flow is slowed as it passes through the pulmonary capillaries."
- **Analysis**: Slowed blood flow allows more time for gas exchange to occur between the blood and the alveoli.
- **Conclusion**: This statement also helps in increasing the efficiency of gaseous exchange.

4. **Evaluating the Third Statement**: "The thickness of the respiratory membrane is increased."
- **Analysis**: An increased thickness of the respiratory membrane would hinder gas exchange because gases would have to diffuse through a thicker barrier, reducing efficiency.
- **Conclusion**: This statement does not help in increasing the efficiency of gaseous exchange.

5. **Evaluating the Fourth Statement**: "The walls of the alveoli and capillaries are very thin."
- **Analysis**: Thin walls facilitate quicker diffusion of gases, thus enhancing the efficiency of gaseous exchange.
- **Conclusion**: This statement helps in increasing the efficiency of gaseous exchange.

### Final Answer:
The statement that will not help in increasing the efficiency of gaseous exchange in the alveoli is: **"The thickness of the respiratory membrane is increased."**

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