Which of the following forms the cerebro-spinal fluid:

Options

A. Choroid plexus
B. Duramater
C. Arachnoid mater
D. Cerebrum and spinal cord

Answer

To determine which structure forms the cerebrospinal fluid (CSF), we will analyze the given options one by one.

### Step-by-Step Solution:

1. **Identify the Options**: The options provided are:
- Choroid plexus
- Dura mater
- Arachnoid mater
- Cerebrum
- Spinal cord

2. **Evaluate Choroid Plexus**:
- The choroid plexus is a network of blood vessels and ependymal cells located in the ventricles of the brain.
- It is responsible for the production of cerebrospinal fluid (CSF).
- **Conclusion**: The choroid plexus is the structure that forms cerebrospinal fluid.

3. **Evaluate Dura Mater**:
- The dura mater is the outermost layer of the meninges that surrounds the brain and spinal cord.
- Its primary function is to protect the brain and spinal cord and to support large venous channels.
- **Conclusion**: The dura mater does not produce cerebrospinal fluid.

4. **Evaluate Arachnoid Mater**:
- The arachnoid mater is the middle layer of the meninges and contains arachnoid villi.
- Arachnoid villi are involved in the absorption of cerebrospinal fluid into the bloodstream but do not produce CSF.
- **Conclusion**: The arachnoid mater does not produce cerebrospinal fluid.

5. **Evaluate Cerebrum**:
- The cerebrum is the largest part of the brain responsible for higher brain functions.
- It does not play a role in the production of cerebrospinal fluid.
- **Conclusion**: The cerebrum does not produce cerebrospinal fluid.

6. **Evaluate Spinal Cord**:
- The spinal cord is part of the central nervous system and is surrounded by cerebrospinal fluid but does not produce it.
- **Conclusion**: The spinal cord does not produce cerebrospinal fluid.

### Final Answer:
The structure that forms cerebrospinal fluid is the **Choroid Plexus**.

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