Mark the incorrect one regarding the structures of a nerve cell ?

Options

A. Dendrites - short and branched fibres which contains receptor proteins on their surface
B. Nissl's granules - found in cyton, dendrites and axon part of neuron
C. Axon - Functional part of neuron that transmit impulses away from the cyton
D. Schwann cell - Synthesises myelin sheath around axons in spinal and cranial nerves

Answer

To solve the question regarding the incorrect statement about the structures of a nerve cell, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding Dendrites**:
- Dendrites are short, branched fibers that extend from the nerve cell body (cyton).
- They have receptor proteins on their surface that receive signals from other neurons.
- **Conclusion**: The statement about dendrites is correct.

2. **Analyzing Nissl Granules**:
- Nissl granules are primarily found in the cyton (cell body) of the neuron.
- They are not present in the dendrites or the axon.
- **Conclusion**: The statement that Nissl granules are found in dendrites and the axon is incorrect.

3. **Examining the Axon**:
- The axon is indeed the part of the neuron that transmits impulses away from the cell body.
- It is a long, slender projection that can extend over great distances.
- **Conclusion**: The statement about the axon is correct.

4. **Looking at Schwann Cells**:
- Schwann cells are responsible for synthesizing the myelin sheath around the axon in both spinal and cranial nerves.
- This statement accurately describes the function of Schwann cells.
- **Conclusion**: The statement about Schwann cells is correct.

### Final Conclusion:
- The incorrect statement regarding the structures of a nerve cell is the one about Nissl granules being found in dendrites and the axon. Therefore, the correct answer is the second option.