This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Intracytoplasmic Nissl granules are found in? 
Select and explain. 
A. Perikaryon of neuron, B. Smooth muscle, C. Skeletal muscle, D. Cardiac muscle
A: Perikaryon of neuron
Answer: A: Perikaryon of neuron 
Explanation: Nissl granules are rough endoplasmic reticulum found in dendrites, but absent in axon or axon hillock. They help in protein synthesis.