Correct Option
The correct option is Rough Endoplasmic Reticulum
Explanation
The cell body (soma) of a neuron contains the nucleus and cytoplasm with typical cell organelles. A distinguishing characteristic of the neuronal soma is the presence of specific basophilic, granular structures known as Nissl’s (or Nissl bodies).
Detailed Analysis:
- Rough Endoplasmic Reticulum (Correct): Nissl’s granules are structurally composed of clusters of Rough Endoplasmic Reticulum (RER) and free ribosomes. Since the RER and ribosomes are the cellular machinery for translation, these bodies are responsible for protein synthesis in the neuron. They produce proteins required for the regeneration of the axon and the synthesis of enzymes and neurotransmitters.
- Neurofibrils (Incorrect): These are fine, thread-like cytoskeletal elements (microtubules and neurofilaments) present in the cytoplasm. Their primary function is to provide structural support and facilitate the intracellular transport of substances, not protein synthesis.
- Mitochondria (Incorrect): While present in the neuron to provide energy (ATP) for nerve impulse transmission and other cellular activities, mitochondria are not the granular bodies associated with protein synthesis.
- Secretory granules (Incorrect): These are vesicles containing synthesized products (such as neurotransmitters) ready for release. They are involved in storage and secretion, rather than the synthesis process itself.
Key Takeaway: Nissl’s granules, found in the cell body of neurons, are the sites of protein synthesis and are composed of Rough Endoplasmic Reticulum and ribosomes.