The fluid which is present outside the cell in Interstitial space forms due to

Options

A. the leakage of fluid outside the blood vessels.
B. the secretions of the choroid plexus of the brain.
C. the gaseous diffusion across the alveoli.
D. All of the above

Answer

To solve the question regarding the fluid present outside the cell in the interstitial space, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Interstitial Fluid**:
- Interstitial fluid is the fluid that exists in the spaces between cells. It plays a crucial role in the exchange of nutrients and waste products between blood and cells.

2. **Analyzing the Options**:
- **Option 1**: Leakage of fluid outside the blood vessels.
- This option suggests that interstitial fluid is formed from fluid that leaks out of blood vessels. This is indeed correct because interstitial fluid is derived from plasma that exits capillaries due to hydrostatic pressure and diffuses into the interstitial spaces.

- **Option 2**: Secretion of choroid plexus of the brain.
- The choroid plexus produces cerebrospinal fluid, which is not related to interstitial fluid. Therefore, this option is incorrect.

- **Option 3**: Gaseous diffusion across the alveoli.
- This option pertains to the exchange of gases (oxygen and carbon dioxide) in the lungs and does not relate to the formation of interstitial fluid. Hence, this option is also incorrect.

- **Option 4**: All of the above.
- Since options 2 and 3 are incorrect, this option cannot be correct.

3. **Conclusion**:
- The correct answer is **Option 1: Leakage of fluid outside the blood vessels**. This is the primary mechanism through which interstitial fluid is formed.

### Final Answer:
The fluid which is present outside the cell in the interstitial space is formed due to the leakage of fluid outside the blood vessels.

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